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题库 / Prep2007E1-SC-2
Organized in 1966 by the Fish and Wildlife Service, the Breeding Bird Survey uses annual roadside counts along established routes for monitoring of population changes of as many as, or of more than 250 bird species, including 180 songbirds.
for monitoring of population changes of as many as, or of
to monitor population changes of as many, or
to monitor changes in the populations of
that monitors population changes of
that monitors changes in populations of as many as, or
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C) D)定语从句，先行词routes，首先monitors主谓不一致，应该是monitor；其次应该是Bird Survey去monitor，不是routes
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