Question

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

1. A.
   had written; left
2. B.
   were writing; has left
3. C.
   had written; had left
4. D.
   were writing; had left

Answer 1

D
考查時態(tài)。句意：當布朗小姐去取落在辦公室的書的時候，學生們正忙于寫作業(yè)。故第一空用過去進行時，第二空用過去完成時。選D。