第9题: [单项选择]The mechanisms ( at )work (are manifest) in the tendency for such physical activity( to )utilize the (potential) harmful constituents of the stress response. A. at B. are manifest C. to D. potential 参考答案:D 答案解析:Potential改为potentially,作状语,修饰harmful。许多考生认为是B项。认为应把are manifest改为are manifested。其实这里的manifest是形容词。