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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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