Question

The students _______ busily when Miss Brown went to get a book she _______ in the office.　

A. had written, left　         B. were writing, has left

C. had written, had left　  D. were writing, had left

Answer 1

D

解析:

“把書(shū)忘在辦公室”發(fā)生在“去取書(shū)”這一過(guò)去的動(dòng)作之前，因此“忘了書(shū)”這一動(dòng)作發(fā)生在過(guò)去的過(guò)去，用過(guò)去完成時(shí)。句中when表示的是時(shí)間的一點(diǎn)，表示在“同學(xué)們正忙于……”這一背景下，when所引導(dǎo)的動(dòng)作發(fā)生。因此前一句應(yīng)用過(guò)去進(jìn)行時(shí)。