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:

當(dāng)分詞的邏輯主語也就是主句的主語，這時可以省去邏輯主語和be動 詞.現(xiàn)在分詞表示主動和進行，而過去分詞表示被動和完成。在這個句子中， 其實是when the drug is taken,省去了the drug is，the drug 和take是被動關(guān)系．