Page 170 - English - Teaching Academic Esl Writing

156 CHAPTER 7
Research has demonstrated that the meanings of aspects create an addi- tional level of complexity for NNSs (Hinkel, 1992; Sharwood Smith & Rutherford, 1988). In teaching L2 writers to use tenses appropriately, it seems that the simpler is indeed the better.
The Perfect Aspect
As mentioned, the perfect aspect combines with tenses to create for a com- plex verb phrase forms and meanings, e.g. the present perfect, hasdevel- oped, or the past perfect, hadcome.The most common verbs that are encoun- tered in the present perfect in academic writing are (in declining order):
has/have + been shown
had, made, seen, become
the rate of 0.1%
the rate of 0.01 %
the rate of 0.004% each
(All rates here and below computed based on the data cited in Biber et al., 1999)
In addition to the relatively infrequent uses of the present perfect, the past perfect verb phrases are hardly ever found in academic writing, and practically all uses entail fo-copula verb that occur with frequency rates of 0.01% per million words (Biber etal., 1999; e.g., Prior tothe 1980s, public ser- vice announcements had been aimed at adults, informing them of possible environ- mental or military dangers). In formal academic writing, however, the past perfect verb phrases tend to occur in the adjective clauses of complex sen- tences (see chap. 10 for more information).
accomodate afford
aim
await
base believe boil compete
comprise depend connect differ consist distinguish constitute doubt contain ensure correspond entitle
cost excuse denote glance
illustrate
induce
inhibit
lean relate matter remember mind represent need require protect resemble
smell suppose want
Verbs Rarely Used in Perfect Tenses
quit reflect regulate
(Adapted from Biber et al., 1999)
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