.
–Who has broken the window in my room?
--Who else ___ it but your naughty son!
| A．could do | B．could have done | C．might do | D．must have done |
Don’ t be joking. It’ s time to______your business.
| A．set out | B．take up | C．go on | D．get down |
Jim went to answer the phone. _____, Harry started to prepare lunch.
| A．However | B．Nevertheless | C．Besides | D．Meanwhile |
When ______questions in class，one should answer them as clearly as possible．
| A．asking | B．to ask | C．to be asked | D．asked |
After the bell rings，which indicates the ending of the exam，you_____stay where you are until all your papers are collected．
| A．shall | B．would | C．will | D．can |
—You were not listening；what troubled you?
—I my coming math exam．
| A．am thinking about | B．was thinking about | C．had thought about | D．will think about |