Question

（2003年上海卷，39）Generally speaking ,        according to the directions , the drug has no side effect .

A．when taking               B．when taken        C．when to take         D．when to be taken

Answer 1

B

解析:

当分词的逻辑主语也就是主句的主语，这时可以省去逻辑主语和be动 词.现在分词表示主动和进行，而过去分词表示被动和完成。在这个句子中， 其实是when the drug is taken,省去了the drug is，the drug 和take是被动关系．