It’s hard to say what kind of person he is. Sometimes he is very nice; at other times he _______ be very cold.
| A．must | B．will | C．shall | D．can |
-- I remember you were a talented pianist at college. Can you play the piano for me?
-- Sorry, I ____ the piano for years.
| A．don't play | B．wasn't playing | C．haven't played | D．hadn't played |
（2012江西卷）--Look! Somebody the sofa.
--Well, it wasn’t me. I didn’t do it.
| A．is cleaning | B．was cleaning | C．has cleaned | D．had cleaned |
（2013·辽宁卷)We are confident that the environmenr by our further efforts to reduce pollution
| A．had been improved | B．will be imroved | C．is improved | D．was improved |
Hard is feeling uncomfortable.He _____ too much at the party last night.
| A．could drink | B．should drink | C．would have drunk | D．must have drunk |
The water supply has been cut off temporarily because the workers ____ one of the main pipes.
| A．had repaired | B．have repaired | C．repaired | D．are repairing |