英语论文网

en they are writing and the frequency is higher than that of other writers. Because using passive voice is good for EST in the clarity of meaning and the objectivity of the whole writing.
The third one is the wide use of the simple present tense. Because the writing in science and technology mainly describes about current issues, present tenses are often used among all tenses , including the simple present, the simple past , the simple future, the present perfect and present progressive, of which the simple present tense is the most basic one. Its use makes the narration without specific time reference.
The fourth one is the preference for replacing existential verbs with action verbs. In EST, action verbs(compared to existential verbs) is more often applied to depict a process, action, phenomenon or development, in this way the description of the whole text will become more vivid and coherent than it would be if existential verbs were used.
2.2.2 The Lexical Characteristics of EST
While studying EST, it is of great help to notice the features of EST vocabulary. It is known that with the development of science and technology, many technical vocabularies have emerged and more and more words are introduced into English. The vocabulary in EST can be classified into two kinds.
The first kind is the highly-technical words. These words are specialized ones in specific fields and with precise and narrow meanings unique to the fields. Besides the highly-technical words, the second kind, the semi-technical words are also found in EST writings. Semi-technical words are words that are employed not only in ordinary English but also in EST. What’s more, their meanings are different in accordance with the requirements of the special fields. In addition to the highly-technical words and the semi-technical words, there is another type of words, that is, formal words. For example, in EST, determined is used instead of find out, construct instead of build, consume instead of use up. These words and expressions are precise, impersonal and formal. The application of these words can also avoid ambiguity in meaning.
2.2.3 The Rhetorical Characteristics of EST
In order to ensure the preciseness and avoid the ambiguity, there is no use of rhetorical expressions in EST writings, such as figures of speech, implied meanings, etc.
Besides, the subjunctives are frequently used. The authors usually adopt it when they give their own idea or supposition in order to avoid arbitrariness. On the other hand, the use of subjunctive can show the humbleness of the author and make the expression more prudent. The use of imperative is also common in EST. In the manuals, different operating procedures and notes imperative is frequently applied to achieve the purpose of advising, warning, and requiring.

Ⅲ. The Nominalization in EST 科技英语的名词化
3.1 The Definition of Nominalization
Nominalization is a very prevalent phenomenon in English. Many dictionaries have given varied editions about the definition of nominalization.
In Oxford Dictionary of Linguistics nominalization is defined as any process by which either a noun or a syntactic unit functioning as a noun phrase is derived from any other kind of unit such as a verb or an adjective.
In Routledge Dictionary of Language and Linguistics (1996), broadly speaking, nominalization refers to every derivation of noun