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题库 / Prep2007E2-SC-120
Although the turtle has been toothless for more than 150 million years, in some contemporary turtle species the moderately sharp and jagged edges of their horny jaws function for teeth.
their horny jaws function for teeth
its horny jaws function for teeth
its horny jaws function as do teeth
the horny jaws function as teeth do
the horny jaws function as teeth
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选错了，自己查了下，这样理解：这里的as不是连词，所以不能选D，function as sth.，起...的作用，作为，充当。
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