Page 302 - English - Teaching Academic Esl Writing

288 CHAPTER 11
teach because parallel sentence elements are highly regular and predict- able in their rigidity.
To begin, the uses of coordinating conjunctionswith simple sentences re- quire that identical or repeated sentence elements be omitted. For example,
(1) ?We measured the thickness of the bar before applying the solvent, and we measured the thickness after applying the solvent.
In this sentence, several elements are repeated in the second sentence: the subject, the verb, and the object, as well as the gerund applying the sol- vent following the preposition after. It is possible to think of these repeated elements as simplifying a basic algebraic expression 2a + 2b = 2(a + b)—when the common elements between the two sentences are placed at the beginning of the sentence and apply equally to all subsequent elements.
In this case, the second occurrences of we measured the thickness of the bar and applying thesolvent would be extracted:
(2) ??Wemeasuredthethicknessofthebarbefore applying thesolvent,and... after... Then the and... after elements that are now left behind with nothing to con-
join should be moved forward tojoin the lonely before with and ... after ...: (3) We measured the thickness of the bar before and after applying the solvent.
The same approach can also be used to eliminate repeated elements of phrases as in the following examples:
*can be measured and can be increased ->
*the metal spoon and the metal bowl -» *largefactories, wholesalers, and big retailers -»
can be measured and ... increased the metal spoon and ... bowl
large factories, wholesalers, and retailers
Another important point to make about using coordinate conjunctions is that they conjoin series of elements that have to be of the same type (e.g., nouns, noun phrases, or gerunds [see chap. 5], verbs or verb phrases of the same tense and number, adjective or adjective phrases, or prepositional phrases). In effect, the term parallel structure refers to "a string" of elements that are similar to beads in a necklace: They can be a little bit different, but not dramatically so. Several examples from an authentic text on sources of the Western tradition are presented next.
Stoicism and itsfollowers taught the universal principles or the natural law.
[Parallel noun phrases in the subject position: The first element of the subject contains a simple noun and the second a noun phrase. Also identical parallel noun phrases in the object position: Both consist of an article, an adjective, and a head noun.]
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