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Q 13 to 15:
Grassland songbirds often nest in
the same grassland-wetland complexes
as waterfowl, particularly in a certain
Line part of those complexes, namely,
(5) upland habitats surrounding wetlands.
Although some wildlife management
procedures directed at waterfowl, such
as habitat enhancement or restoration,
may also benefit songbirds , the impact
(10) of others, especially the control of
waterfowl predators, remains difficult to
predict. For example, most predators
of waterfowl nests prey opportunistic-
ally on songbird nests, and removing
(15) these predators could directly increase
songbird nesting success. Alterna-
tively, small mammals such as mice
and ground squirrels are important
in the diet of many waterfowl-nest
(20) predators and can themselves be
important predators of songbird
nets. Thus. Removing waterfowl-nest
predators could affect songbird nesting
success through subsequent increases
(25) in small-mammal populations.
In 1995 and 1996, researchers
trapped and removed certain waterfowl-
nest predators. primary raccoons and
striped skunks, then observed subse-
(30) quent survival rates for songbird nests.
Surprisingly. They observed no sig-
nificant effect on songbird nesting
success. This may be due to several
factors. Neither raccoons nor striped
(35) skunks consume ground squirrels,
which are important predators of song-
bird nests. Thus, their removal may
not have led to significant increases
in populations of smaller predators.
(40) Additionally, both raccoons and striped
skunks prefer wetlands and spend little
time in upland habitats; removing these
species may not have increased the
nesting success of songbirds in the
uplands enough to allow detection.
Q 15:
The primary purpose of the passage is to A. describe some procedures used for wildlife management and consider some problems associated with the execution of those procedures B. outline a problem related to a wildlife management procedure and offer potential explanations for the results of an experiment bearing on that problem C. present experimental results that illustrate the need for certain wildlife management procedures and point out some inconsistencies in those results D. argue that a certain procedure used for wildlife management should be modified because of its unintended consequences E. propose that further experiments be performed to assess the long-term effects of certain wildlife management procedures
答案是E，我觉得是C，还有人告诉我是B 大家怎么看？ 不要没有回复啊！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
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发表于 2006-10-31 15:45:00
