皮皮学，免费搜题
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搜题
【单选题】
Look at the four squares that indicate where the following sentence can be added to the passage. The defective mucous surfaces will have weakened resistance to bacterial invasion, and their susceptibility to various infections increases. Where would the sA.
Square Ａ.
B.
Square Ｂ.
C.
Square Ｃ.
D.
Square Ｄ.
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参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【判断题】If f is an increasing differentiable function on an interval I, then f'(x)>0 for all x in I.
A.
正确
B.
错误