I am ashamed, sir, that I wasted the many hours _____ I should have studied in class.
| A．while | B．as | C．once | D．when |
______more effectively with foreign firms, many Chinese firms have turned to new technology．
| A．Being competed | B．To compete | C．Competing | D．Competed |
Those books ______ in brown paper are for the kids so that the kids will not easily tear them
up．
| A．to do with | B．done up | C．being done | D．having done over |
You ______ regret all your life if you drive after you take some wine, I tell you．
| A．shall | B．may | C．must | D．can |
．______ he works hard, I don’t mind when he finishes the experiment．
| A．As long as | B．As well as | C．So far as | D．As soon as |
—How long are you staying?
—I don’t know．______．
| A．That’s OK | B．Never mind | C．It depends | D．It doesn’t matter |