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 |
His study was a mess with lots of books and magazines __________up everywhere.
| A．to pile | B．having piled |
| C．piled | D．to be piled |
--Oh, I __________my passport!
--Don’t worry. We have time to go back home and get it.
| A．forget | B．forgot |
| C．will forget | D．had forgot |
While looking for some personal documents, I happened to see an album __________some old photographs.
| A．contained | B．to contain |
| C．containing | D．being contained |
It is more important than ever to develop one’s maths, science and computer skills _______technological change is accelerating.
| A．though | B．unless | C．until | D．because |
_______ patient when you argue with someone who is not so reasonable.
| A．Be | B．Being | C．To be | D．Having been |