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题库 / Prep2007E2-SC-23
Scientists believe that unlike the males of most species of moth, the male whistling moths of Nambung, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
by the use of acoustical signals, but not olfactory ones, and they attract
by the use of acoustical signals instead of using olfactory ones, and attracting
by using acoustical signals, not using olfactory ones, and by attracting
using acoustical signals, rather than olfactory ones, and attract
using acoustical signals, but not olfactory ones, and attracting
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SUBJECT + ACTIVE VERB + BY + NOUN is generally incorrect.**
SUBJECT + ACTIVE VERB + BY + VERBing is generally correct, if "VERBing" is the method or process by which the ACTIVE VERB is carried out.
e.g.
i prepared for the test by studying flash cards --> CORRECT
i prepared for the test by the study of flash cards --> INCORRECT
on the other hand,
SUBJECT + PASSIVE VERB + BY + NOUN is an absolutely fundamental form, if the NOUN is the thing/person that did the action to the SUBJECT.
e.g.
james was seen by two witnesses. --> CORRECT
--
** the only exceptions to this occur in the case of special idiomatic expressions. for instance, "by candlelight" is a known idiomatic expression, so constructions such as "i studied by candlelight" are correct.
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