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题目是TPO11-reading里的“Begging by nestlings”
Paragraph 2：Further evidence for the costs of begging comes from a study of differences in
the begging calls of warbler species that nest on the ground versus those that nest in the relative
safety of trees. The young of ground-nesting warblers produce begging cheeps of higher
frequencies than do their tree-nesting relatives. These higher-frequency sounds do not travel as
far, and so may better conceal the individuals producing them, who are especially vulnerable to
predators in their ground nests. David Haskell created artificial nests with clay eggs and placed
them on the ground beside a tape recorder that played the begging calls of either tree-nesting
or of ground-nesting warblers. The eggs “advertised” by the tree-nesters' begging calls were
found bitten significantly more often than the eggs associated with the ground-nesters' calls.
5. The experiment described in paragraph 2 supports which of the following conclusions?
○ Predators are unable to distinguish between the begging cheeps of ground-nesting and
those of tree-nesting warblers except by the differing frequencies of the calls.
○ When they can find them, predators prefer the eggs of tree-nesting warblers to those of
ground-nesting warblers.
○ The higher frequencies of the begging cheeps of ground-nesting warblers are an
adaptation to the threat that ground-nesting birds face from predators
○ The danger of begging depends more on the frequency of the begging cheep than on how
loud it is.
答案是C。但是文章里没有明说，这类题难道也算推断题嘛？
求解题思路，谢谢啦！ |
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发表于 2011-8-11 15:49:31
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