A sentence is a basic linguistic unit of a text, which can be treated as an independent element to perform the communicative function. The features are said to reflect the scientists’ need for communication and exchanging ideas. To achieve objective, exact and concise statements, EST sentences need to be expressed in well-organized and logical structures. EST texts differ from general English in the use of simple present tense, passive voice, word order and sentence construction. The coming paragraphs discuss some of these features.
A: Extensive Use of the Passive Voice
Passive voices are frequently used in EST from the aspect of syntax on the ground that passive sentence is characterized by its highlighting and objectiveness in expounding sentences. Scientific article as a form of language that reflects the true objective matters appear in our life are to depict the phenomenon, explore the law, illustrate the logical and speculate the correlation among different things. Therefore it is supposed to be expressed objectively so as to get rid of subjective factors and personal feelings. The passive structure can meet the demands of such expression. Scientific papers, irrespective of the deeds by performers, focus on deductive outcomes by the means of exploring the process and interpreting the scientific principles. Then the matters, the process and corresponding results are expected to be placed at the core position of the sentence, and the passive sentence patters are just able to act the role of protruding the object that needs to be explained. Besides, scientific articles pay much attention to accuracy, preciseness and conciseness and frequent using of passive structure can make the sentence compact and concise. According to the statistics by John Swales in LEEDS University of British, at least a third of the predicate is in a form of passive voice. For example:
(1) The results of the research are to be published soon.
(2) The temperature of the liquid is raised by the application of heat.
(3) The growth was affected by radiation.
Anther pattern of passive model commonly found in EST texts is the ‘it’ construction:
is well known
is usually considered
It + should be made clear that
has been reported
can be assumed
In instructions, warnings and notices, passive models are particularly common. This type of passive construction may suggest the formality of EST style.
Passive voice is extremely useful and sometimes even regarded as mandatory in expressing objective ideas in EST, such as scientific or technical reports, where the actor is not the most important element and the concepts or principles being conveyed are absolutely important. Therefore, in order to achieve objectivity, the passive voice is extensively used in EST texts.
B. Predominant Use of Long Sentences
Long sentences, which are frequently used in EST texts to illustrate the inner link among scientific facts or phenomena, to interpret scientific and technological terms and describe the technological process, is another characteristic of the EST. In order to depict the facts or phenomena precisely, many grammatical means are applied in the sentences, such as a variety of subordinate clauses, phrases and complex structures. Those means are to modify and complement the main contents of the sentences, causing the emergence of complicate and long sentences, which brings more difficulties to readers in understanding and digesting the original text. Here cite an obvious example as follows:
Original: A gas may be defined as a substance which remains homogeneous, and the volume of which increase without limit when the pressure on it continuously reduced, the temperature being maintained constant.
This sentence contains two attributive clauses and one adverbial clause. They are respectively the attributive clauses that are led by “which” and the adverbial clause that is led by “when”. As a matter of the fact, backbone of this sentence is very simply, that is “a gas may be defined as a substance”, and the first “which” attributive clause is to modify the “substance”, the second “which” clause refer to “the volume of gas”. The usage of “which” attributive clause makes the sentence more compact and precise, which conforms to the features of EST style.
According to The Contemporary English Grammar, nominalization is one of features of EST. the usage of nominalization in general English is much less than that of EST text, meanwhile the structure of general English is more simple compared with EST text. The definitions, theorems, formations and abstract conception involved in EST text are more frequent than general articles. What’s more, the EST is needed to be equipped with the characteristics that are concise construction, objective expression and exact information, etc. Nominalization is regarded as an important way to make sentences impersonal and compact, and is probably evolved at the very beginning in scientific and technical text, where it plays a dual role “to establish hierarchies of technical terms and to have an argument step by step, using complicated passages packaged in nominal form as themes”.3 Thus nominalization is frequently used in EST texts. Look at the following examples:
(1) The development of the rocket makes it possible for man to enter space.
(2) Knowledge of the forces on the gear makes possible the determination of its size.
“The development of the rocket” and “man to enter space” in example (1) are noun phrase, which make the sentence much more concise and logical. And in example (2) we seldom express it like “if we know the forces on the gear we can determine its size” for nominalization makes the sentence more abstract, inclusive and concise.