Comparative Study of Czech and English Passive Voice in ESP

Voz activa y pasiva en IFE: estudio comparativo de inglés y checo

LibuŇ°e Turinsk√° (Institute of Technology and Business in ńĆesk√© Budńõjovice)

Karim Sidibe (Institute of Technology and Business in ńĆesk√© Budńõjovice)

Artículo recibido: 21-12-2016 | Artículo aceptado: 04-03-2017

RESUMEN: La voz pasiva se define como la construcci√≥n gramatical en la que el objeto del verbo se presenta en la posici√≥n del sujeto. La voz pasiva en el checo e ingl√©s tienen la misma estructura b√°sica. Sin embargo, la voz pasiva en el checo tiene dos formas, la perifr√°stica y la reflexiva, la que es completamente diferente de la forma inglesa. El art√≠culo tiene como objetivo analizar la frecuencia de las construcciones pasivas presentes en los textos t√©cnicos presentados en l√≠nea y entonces confirmar la hip√≥tesis de la influencia negativa que la lengua materna tiene sobre el estudio de la voz pasiva, as√≠ como se√Īalar la importancia de ense√Īar dentro del marco de cursos de IFE e ICT. Para obtener los datos b√°sicos, veinte textos t√©cnicos en l√≠nea han sido seleccionados para el an√°lisis. El software AntConc versi√≥n 3.4 ser√° utilizado para recoger los datos. Los datos ser√°n analizados y comparados para determinar la frecuencia del uso de pasivo en ambos idiomas.
ABSTRACT: Passive voice can be defined as a construction in which the object of a verb appears in the position of a subject. English and Czech share the basic structure in the formation of passive. The aim of the article is to analyse the occurrence of passive constructions in technical articles available online and thus confirm the assumption of the existence of negative influence of language interference on the acquisition of the passive voice for Czech ESP students as well to point out the necessity to include passive voice in the curriculum of ESP. In order to get the basic data, twenty online articles, ten in Czech, ten in English, on the topic related to mechanical engineering were selected. For the data collection, the AntConc software version 3.4 was used. The data gathered were subsequently analysed and compared to confirm the hypothesis of higher frequency of using passive voice in English technical texts and thus to emphasize the importance of studying and teaching passive voice within ESP.

PALABRAS CLAVE: MVoz activa, voz pasiva, agente, IFE (Inglés para Fines Específicos), ICT (Inglés para Ciencias y Tecnología)
KEY WORDS: Active voice, Passive voice, agent, ESP (English for Specific Purposes), EST (English for Science and Technology)


The scientific study was created during the project No. 201609 of the Internal Grant Competition at the Institute of Technology and Business in ńĆesk√© Budńõjovice.


1. Introduction

English for Specific Purposes (ESP) has actually become one of the most studied fields in terms of learning and acquisition of English. Based on the learners¬ī needs analysis (LNA), it aims to provide the students with the practical knowledge of the specific or technical vocabulary needed for their field of study as well as a certain amount of necessary grammar structures ‚Äď necessary for adequate comprehensible expression of a particular, specific topic.

According to Hutchinson and Waters (1987), ESP can be further divided into three categories: English for Science and Technology, English for Business and Economics and English for Social Studies. This comparative study is targeted at EST students (hereinafter referred to as EST), in particular students of English for mechanical engineering.

EST or ESP as such focuses on teaching vocabulary and target language in context, therefore teaching grammar might be neglected in some of them.

This paper aims to highlight the importance of studying and teaching passive voice for the specific needs of EST students by identifying the occurrence of passive constructions in English and Czech online technical texts and subsequently comparing their frequency.

2. Passive voice

Voice is a grammatical category of verbs in most languages. In both English and Czech, the category of voice is realized through the opposition of active and passive voice. The basic definition is almost the same in both languages. As Nida (1964) claims, voice is considered a linguistic category defining the relationship between the participants and the event indicated in the verb. According to Britannica, linguistic category of voice is a “form of a verb indicating the relation between the participants in a narrated event (subject, object), and the event itself. Czech linguistic publications mostly define the voice of a verb as a grammatical, morphological means of expressing the relationship between the elements of semantic structure of a sentence and their syntactic position, that is, if the agent is in the position of a subject in the sentence. Both languages distinguish between two types of verb voice: active and passive.

2.1. Structure of English passive voice

Passive voice can be defined as a construction where the object of transitive verb appears as its subject (Trask, 1993). The basic construction of passive voice in English consists of an auxiliary verb and a past participle form of a lexical verb, where the auxiliary verb indicates the verb tense and the number of participants. In spoken English, another form of passive is possible, using to get in the position of the auxiliary verb instead of to be. For the needs of this comparative study, only to be passive as a form of passive occurring in both languages will be taken into account.

In English, each verb tense has its passive voice (see Table 1).

 

Verb tense Passive voice
Present simple The problem is discussed.
Past simple The problem was discussed.
Present perfect simple The problem has been discussed.
Past perfect simple The problem had been discussed.
Simple future ‚Äď will

                       Рgoing to

The problem will be discussed.

The problem is going to be discussed.

Future perfect simple The problem will have been discussed.
Present progressive The problem is being discussed.
Past progressive The problem was being discussed.

Table 1:English passive voice – verb tenses. Source: Authors

As shown in Table 1, all simple verb tenses have passive voice. As for the progressive forms, DuŇ°kov√° (1994) says that there might be passive voice of progressive verb tenses other than present and past progressive. However, those are rejected by most native speakers.

2.2. Structure of Czech passive voice

Czech language distinguishes between two basic forms of passive constructions. The periphrastic form of passive voice is equivalent to the English one, using the auxiliary verb to be indicating the tense and number of participants and passive participle of lexical verb (called n/t- participle), indicating the genre and number of participants (Karlík, 2004). The reflexive form of passive uses a reflexive particle se and a lexical verb in a particular tense. Both forms of passive voice occur in all verb tenses, and in some cases they can be used interchangeably (see Table 2).

 

Tense Periphrastic passive Reflexive passive
Past DŇĮm byl postaven/ DŇĮm byl stavńõn. DŇĮm se postavil / DŇĮm se stavńõl.
Present DŇĮm je postaven. / DŇĮm je stavńõn. DŇĮm se stav√≠.
Future DŇĮm bude postaven / DŇĮm bude stavńõn. DŇĮm se bude stavńõt.

Table 2: Czech passive voice ‚Äď verb tenses. Source: Authors

2.3. Using passive voice

In both languages, there appear verbs that cannot be used in passive voice. As DuŇ°kov√° (1994) states, in English those are intransitive verbs (e.g. go, stay, happen, arrive), that is, verbs that do not take an object complement, and certain state verbs (e.g. have, belong, resemble etc.). Similarly in Czech, Kom√°rek, KoŇôensk√Ĺ, Petr, Veselkov√° et al. (1986) claim that passive cannot be formed from intransitive verbs (e.g. j√≠t/go, Ňĺ√≠t/live, st√°rnout/grow old, prŇ°et/rain), transitive verbs expressing mental state or physical condition (e.g. P√°l√≠ ho ońći. Bol√≠ mńõ hlava.) as well as those expressing movements of parts of human body (e.g. Sklopil ońći. Zvedl hlavu.) and most reflexive verbs using se morpheme (sm√°t se / laugh, posm√≠vat se / mock, odvdńõńćit se / repay).

In terms of ditransitive verbs (verbs using both direct and indirect object), DuŇ°kov√° (1994) says in English both direct and indirect object may appear in the position of subject. However, in Czech only direct object can be placed in the position of subject.

As for the word order, English passive constructions have a fixed specific syntactic word order. In such constructions, the word order is as follows:

Subject + be + past participle + object / agent

The problem + has been + discussed + by the participants

In Czech, in contrast, word order is not fixed (Bischofov√°, 2001), placing rheme in the end-position.

English Czech
The information was given to all participants. Informace byly pŇôed√°ny vŇ°em √ļńćastn√≠kŇĮm
VŇ°em √ļńćastn√≠kŇĮm byly pŇôed√°ny informace

 

From the example given it results that it depends on the subjective opinion of the speaker which information is considered to be new, clue or the most important one.

There are a number of linguists distinguishing between various forms of passive in various languages (Quirk, 1972, Granger, 1983, Fern√°ndez, 1998). In terms of analysing the differences between English and Czech passive voice, Quirk¬īs classification (1972) seems to be the most appropriate one, distinguishing between three types of passive:

  1. Agentive passive, where the agent is expressed and used with preposition by: Finite sources of energy will soon be replaced by alternative ones.
  2. Quasi-passive: John was interested in linguistics.
  3. Non-agentive passive: The house is already sold.

Similarly, in Czech, the agent as a doer of the action does not have to be expressed. In both languages this occurs when the agent is unknown, included in the action or not important. However, Czech as a flectional language expresses the agent by linguistc category ofcase, in particular, by means of the instrumental case.

All differences in passive voice arising from the form, structure and type of passive may result in misinterpreting the information sought in technical texts.

3. Methods

The aim of the article was to do a review on the frequency of the passive voice in English and Czech. The hypothesis to be confirmed was based on the assumption that the passive voice constructions in technical writing will be more frequent in English than in Czech. In order to identify and analyse the occurrence of passive constructions in EST (English for mechanical engineering in particular), in total twenty online technical texts (ten in English, ten in Czech) were selected, all of them on a similar topic related to mechanical engineering. Those topics were selected in correspondence with the syllabus of the English for Mechanical Engineering courses and textbooks available in the Czech Republic.

The online texts were first downloaded and converted into .txt format and fed into AntConc freeware corpus analysis toolkit for concordance and text analysis. The data obtained were subsequently numerically treated and compared.

3.1. Results and discussion

3.1.1. Source texts

All articles were selected based on the following criteria:

– The articles must be available online;

– The topic of the articles must relate to mechanical engineering;

– The topics of the articles must be the same or almost the same both in Czech and English.

The articles being analysed and compared include the following topics: Global positioning system, Nanotechnology in medicine, 3D printing, CAD, Alternative sources of energy, Drones, metal forming processes, turbines. The following table (Table 3) shows the topics of the online articles in English and Czech. The URL addresses for each of the article are attached in Appendix 1.

Headline in English Headline in Czech Topic
Acrobat 3D Software to accelerate Design Collaboration Processes at Renault Group Akrobat 3D urychlí procesy spolupráce na návrzích u skupiny Renault Group CAD
What is GPS? O technologii GPS GPS
Introduction to Deformation Processes Tv√°Ňôen√≠ kovŇĮ Metal forming processes
This drone is one of the most secretive weapons in the world Odtajnńõn prvn√≠ let britsk√©ho dronu Taranis Drones
The most common alternative energy sources Obnovitelné zdroje energie Alternative sources of energy
A third industrial revolution 3D tisk: TŇôet√≠ prŇĮmyslov√° revoluce 3D printing
Nanotechnology in Medicine L√©ky menŇ°√≠ neŇĺ buŇąka. Budoucnost medic√≠ny je v nanotechnologii Nanotechnology
Electric car boom raises pollution fears Elektromobily zneńćiŇ°Ň•uj√≠ ovzduŇ°√≠ v√≠c neŇĺ spalovac√≠ motory, vypl√Ĺv√° z anal√Ĺzy Automotive
Automotive industry Automobilov√Ĺ prŇĮmysl Automotive
How does Francis turbine work? Francisova turbína Turbines

Table 3: Topics and headlines of online articles used. Source: Authors

When analysing and comparing the frequency and occurrence of passive voice constructions, only the shared basic structure of periphrastic passive voice (to be + past participle) in both languages was taken into consideration. Subsequently, the occurrence of reflexive passive form in Czech was analysed in order to show the contrast and to show a possible source of misinterpretation of some information contained in the online texts. Participle clauses (-ed clauses: The company founded in Austria has its headquarters in Vienna.) were not included in the analysis. The authors focused mainly on the frequency of passive constructions, tense used and the presence of the agent of the event. To see the results of the analysis, compare Graph 1 and Graph 2.

3.1.2.English and Czech passive constructions occurrence

Graph 1 and Graph 2 show the occurrence and frequency of using periphrastic passive constructions in English and Czech in terms of the total number of the passive constructions used and verb tense.

Graph 1 Number of periphrastic passive constructions in English texts. Source: Own processing
Graph 1 Number of periphrastic passive constructions in English texts. Source: Own processing

Graph 1 shows the occurrence and frequency of using periphrastic passive constructions in English in terms of the total number of the passive constructions used and verb tense used. In the analysed English texts 183 passive constructions appeared in total. The most frequently used tense was the present simple, used in 167 cases which accounts for almost 91 %. The share of the passive constructions in other tenses is significantly smaller, with only seven passive constructions (less than 4%) in past simple and present continuous, five in simple future (less than 3%) and six (3%) in the present perfect simple tense.

In terms of agentive passive constructions, only as much as twenty out of 183 passive constructions (less than 11%) appeared with the agent expressed, attached to the passive construction by the preposition by.

The online texts in Czech were subjected to the same analysis. Graph 2 shows the data referring to the periphrastic form of passive voice.

Graph 2. Number of Be + past participle passive constructions in Czech texts . Source: Own processing
Graph 2. Number of Be + past participle passive constructions in Czech texts . Source: Own processing

The data presented in Graph 2 show that in ten online Czech texts, the total number of periphrastic passive constructions is 57. Similarly to English, from this number, the overwhelming majority of 43 passive constructions appeared in present tense, simple or continuous, which accounts for 75%. Only thirteen passive constructions were used in past tense (less than 23%).

As for the agentive passives, from the total number of 57 passive constructions, in only eight cases (15%) the agent of the event was expressed by means of the instrumental case.

3.1.3. Analysis and comparison

As the articles presented online differ significantly in their length, it is not possible to compare their frequency and occurrence by simply comparing the number of them in both English and Czech online texts. In order to show the difference clearly, the number of verbs in active voice was determined and subsequently compared with those in passive voice, showing the ratio between the active and passive voice. The results showed that the ratio between English passive and active voice was 183:496, which is about 1:3. In Czech, the active voice prevailed over the passive one as well, but with a significantly higher ratio of 57:606, that is almost 1:10.

The reflexive passive was not taken into account for the needs of the article, that is, for the comparison of the frequency in the use of passive voice, as it focused on periphrastic passive constructions, which share the same structure both in English and in Czech. However, the following numbers show it plays an important part when dealing with technical texts.  When analysing the occurrence and use of Czech passive constructions, it was found out that the number of reflexive passive constructions in the Czech texts prevailed significantly over the periphrastic ones by 42 to 28, that is, 1.5:1. Like in the case of periphrastic passive, the majority of the reflexive passive constructions were used in present tense. The share of the individual tenses was 9% (4) in past simple, only one of them in the future simple (about 2%) and 37 (88%) in present tense.

3.1.4. Discussion

At the beginning of this comparative study, the hypothesis was formulated claiming that in terms of frequency of using passive voice in online technical texts, English passive is more frequently used than in Czech. This hypothesis was confirmed, as seen in Graph 1 and Graph 2. Moreover, it may be assumed from the difference between both languages in terms of passive voice forms that Czech EST students might have problems with the comprehension of the information contained in the English texts. As mentioned in the theoretical part of the study, in Czech language it is possible to use the reflexive passive construction which is frequently interchangeable with the periphrastic passive constructions.

As a significantly more frequently used form of passive, which does not have equivalent in English, the reflexive form of passive voice in Czech plays an important part in terms of the inter-language interference which might negatively influence the students’ ability to learn about using passive constructions in English. By pointing out the difference, teachers may enhance students’ comprehension of passive voice structures.

Most analysed texts are either descriptions of some specific technical process, technologies or actual news from the field of mechanical engineering. Therefore, in terms of the tense used, in both languages prevails the use of simple present (English) or present (Czech) tense, accounting for 97% of all verbs in passive voice in English and 75% of Czech verbs in passive voice.

When analysing and comparing the online texts, it was found out that some verbs are preferably used in passive rather than active voice. A concordance between English and Czech was identified in terms of verbs use (EN) /pouŇĺ√≠vat (CZ) and call (EN)/ naz√Ĺvat (CZ) as the most frequent verbs used in passive voice.

 

English Czech
Call: It¬īs what¬īs called a demonstrator.

…a phenomenon which might be called social manufacturing.

Some of them are called automakers.

This procedure is called product recall.

They are also called ‚Äúmixed flow turbines‚ÄĚ.

Naz√Ĺvat: Stroje na v√°lcov√°n√≠ se naz√Ĺvaj√≠ v√°lcovac√≠ stolice.

Druhou prŇĮmyslovou revoluc√≠ se naz√Ĺv√° n√°stup internetu v 90. letech minul√©ho stolet√≠

 

Use: Other techniques are actually being used today.

… gelatin nanoparticles can be used to deliver drugs…

… that may eventually be used for non-invasive surgery.

Cold rolling is often used in the final stages of production.

The process can be used for most materials.

…which are used both to apply the tensile force

Stamping is used to make high volume parts

The signals are used to calculate the exact position.

… coal power alone was used to charge electric cars.

‚Ķ it¬īs being used to test technologies

… test technologies that may be used in future aircraft,

… wind energy was used to turn mechanical machinery …

… large scale wind farms that are used by national electrical grids

Solar energy is used commonly for heating

Solar energy can be used very efficiently for practical uses

…the steam that shoots up is purified and is used to drive turbines

… flow of water can be used to turn turbines

Water used for hydro power can be reused to…

… but it is already being used to make specialist parts for cars   

Mass given in tons (metric tons) is used as a limit

Minibuses, …, are used for the transport of passengers

Buses and coaches are used for the transport of passengers

The guide vane mechanism is used to control water flow rate

PouŇĺ√≠t: Dnes se GPS pouŇĺ√≠v√° v des√≠tk√°ch pŇô√≠strojŇĮ.

Energie vńõtru je v¬†dneŇ°n√≠ dobńõ vyuŇĺ√≠v√°na pŇôedevŇ°√≠m k¬†v√Ĺrobńõ elektŇôiny.

Vodn√≠ energie je vyuŇĺ√≠v√°na pro v√Ĺrobu elektŇôiny.

Pro v√Ĺrobu elektŇôiny se vyuŇĺ√≠v√° proudńõn√≠ vody.

Pro energetick√© √ļńćely se vyuŇĺ√≠v√° c√≠lenńõ pńõstovan√° rostlinn√° biomasa.¬†

Biomasa mŇĮŇĺe b√Ĺt vyuŇĺita pro v√Ĺrobu elektŇôiny

VyuŇĺ√≠v√° se ve sv√© z√°kladn√≠ formńõ

… v¬†ńĆesk√© republice se geoterm√°ln√≠ energie pouŇĺ√≠v√° na vyt√°pńõn√≠…

Nejprve se tento motor uŇĺ√≠val ve stroj√≠rensk√Ĺch podnic√≠ch…

…po zlepŇ°en√≠ (zejm√©na odlehńćen√≠) zańćal b√Ĺt pouŇĺ√≠v√°n tak√© k pohonu automobilŇĮ

V USA¬†se tento syst√©m pouŇĺ√≠val jiŇĺ dŇô√≠ve.

PouŇĺ√≠vaj√≠ se pro produkci elektrick√© energie.

Francisovy turb√≠ny se pouŇĺ√≠vaj√≠ v energetice.

PouŇĺ√≠v√° se pro stŇôedn√≠ a vńõtŇ°√≠ prŇĮtoky a sp√°dy.

Poprv√© vŇ°ak byla kotouńćov√° brzda pouŇĺita jiŇĺ roku 1906

 

 

In terms of the frequency of periphrastic passive voice, a significant difference was noted between Czech and English online texts. The periphrastic form of passive voice in Czech seems to be replaced very often by more preferred reflexive passive voice in all tenses. This might pose a problem for Czech students when acquiring the periphrastic passive voice in general English, as a number of them might not be even aware of reflexive and periphrastic passive being equal in many cases. As the passive voice is used more frequently in technical texts, this may result in misinterpretation of the texts. Moreover, Czech reflexive passive does not have equivalent in English. It might therefore be a problem when trying to express the ideas in English. The structure of English clauses itself might cause problems when translating into English, as the subject in the Czech sentence does not have to be expressed, while it is a basic rule to start with a subject when constructing sentences in English.

Translating periphrastic passives from English may cause other difficulties, as in many cases, it is not possible to use literal translation of the construction.

Another complication for the right employment of passive voice poses the verb tense. English tense system is complicated for Czech students, as in Czech, there are only three basic verb tenses ‚Äď past, present and future (ńćas minul√Ĺ, pŇô√≠tomn√Ĺ and budouc√≠ – compare Graph 1 and 2). This may result in more problems with misunderstanding or misinterpretation when trying to describe any technical problem or process in English. Language interference plays a huge role when producing a message in English.

According to CEFR, passive voice is taught at the B1 level of general English. The EST students should thus be familiar with its construction and use. As passive voice is not used in spoken Czech very often, it seems to be forgotten soon if not practiced properly. Every EST textbook should therefore contain at least one basic exercise for practicing namely basic passive constructions in the most commonly used tenses (see Graph 1), that is, in simple present and past. It would be also convenient to point out any passive construction used both in the textbook texts as well as in any online sources being used and especially at the beginning of the course, ask the students to translate or paraphrase the sentences where passive constructions are used.

4. Conclusion

Passive voice is a grammar category used both in English and Czech. In both languages, using passive voice constructions is a typical feature of scientific or technical texts. Both languages share the basic structure of periphrastic passive voice, that is, to be in the position of an auxiliary verb and a past participle of a lexical verb. However, there are also differences resulting from a different type of language, for example different tense system, flectional vs inflectional language etc. Moreover, Czech language uses a reflexive form of passive voice, which does not have an equivalent in English and has to be translated or expressed using periphrastic passive. As this form seems to be used much more frequently than the conventional, shared form of passive, the interlanguage interference negatively affects especially the translation process from English to Czech and a vice versa.

It results from the analysis of texts which might be used as a source of information for the EST courses or for studying and teaching English for mechanical engineering, and comparing the frequency of using passive voice that this construction should be given more attention to when teaching ESP in general or EST.

5. Works Cited

Bischofov√°, Jana (2001). Prahov√° √ļroveŇą: ńćeŇ°tina jako ciz√≠ jazyk. Strasbourg: Council of Europe Publishing.

DuŇ°kov√°, LibuŇ°e (1994). Mluvnice souńćasn√© anglińćtiny na pozad√≠ ńćeŇ°tiny.Prague: Academia.

Encyclopaedia Britannica. https://www.britannica.com/topic/voice-grammar#ref31566  (4-9-2016)

Fern√°ndez, Julia L√≥pez (1998). La voz pasiva y la construcci√≥n impersonal en espaŇąol: Dos manerasde presentar, manipular y seleccionar informaci√≥n. ASELE. Actas IX. http://cvc.cervantes.es/ensenanza/biblioteca_ele/asele/pdf/09/09_0570.pdf (4-10-2016).

Granger, Sylviane (1983). The be + past participle construction in spoken English. New York: Oxford.

Hutchinson, Tom and Alan Waters (1987). English for Specific Purposes: A learning-centred approach. Cambridge: Cambridge University Press.

Karlík, Petr and Ludmila Veselovská (2004). Analytic passives in Czech. Berlin: Akademie Verlag.

Kom√°rek, Miroslav; KoŇôensk√Ĺ, Jan; Petr, Jan, Veselkov√°, Jarmila et al. (1986). Mluvnice ńćeŇ°tiny. Praha: Academia.

Nida, Eugene Albert (1964). Towards a science of translating: With special reference to principles and procedures involved in Bible translating. Leiden: Brill Archive.

Quirk, Randolph; Greenbaum, Sidney; Leech, Geoffrey and Jan Svartvik (1972). A grammar of contemporary English. London: Longman.

Trask, Robert Lawrence (1993). A dictionary of Grammatical terms in linguistics. London: New York.

6. Appendix

Sources:

Article headline URL
Acrobat 3D Software to accelerate Design Collaboration http://www10.mcadcafe.com/nbc/articles/view_article.php?articleid=369734
Akrobat 3D urychlí procesy spolupráce na návrzích u skupiny Renault Group http://www10.mcadcafe.com/nbc/articles/2/372943/Acrobat-3D-Accelerates-Renaultrsquo;s-Design-Collaboration-Processes
What is GPS? http://www.mio.com/technology-what-is-gps.htm
O technologii GPS https://eu.mio.com/cs_cz/global-positioning-system.htm
Introduction to Deformation Processes http://www.doitpoms.ac.uk/tlplib/metal-forming-2/printall.php
Tv√°Ňôen√≠ kovŇĮ http://www.bogner.cz/files/files/Tvareni_kovu_mechanicke_opracovani_tazeni_brouseni_loupani_valcovani_kovani.pdf
This drone is one of the most secretive weapons in the world http://www.businessinsider.com/british-taranis-drone-first-autonomous-weapon-2015-9
Odtajnńõn prvn√≠ let britsk√©ho dronu Taranis http://www.osel.cz/7469-odtajnen-prvni-let-britskeho-dronu-taranis.html

 

The most common alternative energy sources https://www.thebalance.com/the-most-common-alternative-energy-sources-2941105
Obnovitelné zdroje energie http://www.nazeleno.cz/obnovitelne-zdroje-energie.dic
A third industrial revolution http://www.economist.com/node/21552901
3D tisk: TŇôet√≠ prŇĮmyslov√° revoluce http://www.ekontech.cz/clanek/3d-tisk-treti-prumyslova-revoluce
Nanotechnology in Medicine http://www.understandingnano.com/medicine.html
L√©ky menŇ°√≠ neŇĺ buŇąka: Budoucnost medic√≠ny je v nanotechnologii http://zoom.iprima.cz/clanky/leky-mensi-nez-bunka-budoucnost-mediciny-je-v-nanotechnologii

 

Electric car boom raises pollution fears https://www.ft.com/content/3cb0dd38-83ff-11e6-8897-2359a58ac7a5

 

Elektromobily zneńćiŇ°Ň•uj√≠ ovzduŇ°√≠ v√≠c neŇĺ spalovac√≠ motory, vypl√Ĺv√° z anal√Ĺzy https://www.novinky.cz/veda-skoly/280666-elektromobily-znecistuji-ovzdusi-vic-nez-spalovaci-motory-vyplyva-z-analyzy.html

 

Automotive industry https://en.wikipedia.org/wiki/Automotive_industry
Automobilov√Ĺ prŇĮmysl https://cs.wikipedia.org/wiki/Automobilov%C3%BD_pr%C5%AFmysl
How does Francis turbine work? http://www.learnengineering.org/2014/01/how-does-francis-turbine-work.html
Francisova turbína http://www.vodniturbiny.cz/index.php?linkid=05
Caracteres vol.6 n2

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Caracteres. Estudios culturales y críticos de la esfera digital | ISSN: 2254-4496 | Salamanca