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 |
— He is a very hard-working student．
—．As far as I know, he often burns the midnight oil．
| A．You can say that again | B．Absolutely not | C．Heaven knows | D．No way |
—Guesswhat!Icameacrossanoldfriendatthepartylastnight.
—____________！I’msureyouhadawonderfultime.
| A．Soundsgood | B．Verywell | C．Allright | D．Hownice |
______ around the cultural relics for almost an hour, we got together under a big tree for a short break.
| A．Having shown | B．Having been shown |
| C．To show | D．To be shown |
---He ought to have been warned of the danger.
---_______, but he wouldn’t listen to me.
| A．He did | B．He should | C．He ought to | D．He was |
---You may find the key to the maths problem on page 107.
---Ah, it’s so simple. I wonder why I ________ of that.
| A．didn’t think | B．haven’t thought | C．wasn’t thinking | D．hadn’t thought |