Question

【題目】Only when class began ______ that he had left his book at home.

A. will he realizeB. he did realize

C. did he realizeD. should he realize

Answer 1

【答案】C

【解析】

考查倒裝結(jié)構(gòu)。當(dāng)only等詞謂語句首時，主句采用部分倒裝，句意：直到上課開始時，他才意識到他已經(jīng)把書丟在家里面了。結(jié)合語境可知此處描述的是過去的動作，故用過去時態(tài)，助動詞用did，故選C。