—I don’t understand why you didn’t go to the lecture yesterday afternoon.
—I’m so sorry.But I________my homework.(2013·湖南，34)
A．had done B．was doing
C．would do D．am doing
If nothing________，the oceans will turn into fish deserts.(2013·湖南，26)
A．does B．had been done
C．will do D．is done
Around two o’clock every night，Sue will start talking in her dream.It somewhat________us. (2013·湖南，24)
A．bothers B．had bothered
C．would bother D．bothered
The water supply has been cut off temporarily because the workers________one of the main pipes. (2013·天津，13)
A．had repaired B．have repaired
C．repaired D．are repairing
We are confident that the environment________by our further efforts to reduce pollution. (2013·辽宁，30)
A．had been improved B．will be improved
C．is improved D．was improved
He was unhappy when he sold his guitar.After all，he________it for a very long time.
(2013·辽宁，22)
A．has had B．had had
C．has D．had
