问题
选择题
________ entered the classroom _________ the bell rang.
A．We hardly had, before
B．Hardly had we, when
C．Hardly had we, than
D．Hardly did we, when
答案
答案：B
hardly…when… “一…就…”。Hardly开头句子采用部分倒装而且后面的句子时态用过去完成时，when后的句子不倒装而且用一般过去时态。所以选B。
为f（x）的一个原函数，则下列（）项为
