Grammar, Punctuation and Capitalization - Handbook for Technical ...

Chapter 2. Sentence Structure Page 27sentence, indication is not the true subject; in the second sample, the subject and verb positions have been wastedby an indirect construction, there is.Effective Revenue Writing 2 (Linton 1962) suggests that the real subject of a sentence can be found by identifyingthe real action in the sentence; the subject is then either receiving the action or preferably performing it. In the firstsample sentence, identify the action. From among the several words of action (indication, reduction, operation, isshown, presented), indication seems most important. Two revisions come to mind when indicate becomes themain verb:Asymmetric throat area reduction between the upper and lower throats of this nozzle duringreverse thrust operation is probably indicated by the jet lift coefficients presented in figure 28.The jet lift coefficients presented in figure 28 indicate a probable asyrnmetric throat area reductionbetween the upper and lower throats of this nozzle during reverse thrust operation.Which sounds best? The second revision, with an active verb close to its subject, is certainly easier to read. Outof context, it is preferable. Context affects the choice of subject. For good transition from one sentence toanother, the subject of a sentence should relate to the previous sentence.Now consider the second sample sentence, containing the indirect construction. The expletive there forces the trueaction of the sentence, indicating, into a participial construction. Making indicate the main verb results inAt NPR < 4, a large reduction in discharge coefficient due to reverse thrust operation indicates adecrease in the effective throat area for the nozzles.Another indirect construction involves the pronoun it:IndirectBetterIndirectBetterIt appears that grain refining improved the toughness ofmaraging steels.Grain refining seemed to improve the toughness ofmaraging steels.It is obvious that a blackbody laser is feasible as a spacepower system.Obviously a blackbody laser is feasible as a space powersystem.As with any valid grammatical construction, indirect constructions sometimes serve a function, but manygrammar and writing books criticize them as being wordy (see section 2.4.1) and unnecessary. Rowland (1962)states that "expletives serve only to mark time until the true grammatical subject appears." In Tichy andFourdrinier's (1988) opinion, as well as in Rowland's, indirect constructions can be ambiguous. Such idioms as"it is known" or "it is believed" indicate general knowledge or belief:It is believed that this is a nozzle-aspect-ratio effect.In most technical writing, these constructions refer to the author's belief or knowledge. Perhaps a personalpronoun is appropriate (see section 1.3.2):We believe that this back pressure increase is a nozzle-aspect-ratio effect.Note the change in the subordinate clause of this sentence. Demonstrative pronouns (this, these, that, or thoseused as nouns) with "broad reference" (Ebbitt and Ebbitt 1982) can be undesirable and ungrammatical when theirantecedent is not clear (see section 1.3.1):