For many years, ____ animals for carrying food and other supplies from one area to another has been a means of living in Xinjiang Autonomous Region .
| A．trained | B．training | C．having trained | D．to have trained |
You________ the work better, but you didn’t put more efforts to it.
| A．must have done | B．can have done | C．should have | D．could have done |
The professor you referred to in the letter______ us students three lectures by next Monday.
| A．has given | B．will given | C．will have given | D．Gave |
—What do you think has caused his heart attack?
—It is ______.
| A．because of his overweight | B．due to his being overweight |
| C．his being overweight | D．he is so overweight |
—Do you have any idea why the engineer resigned?
—No. In fact, everyone is ____about it.
| A．doubtful | B．curious | C．enthusiastic | D．annoyed |
It’s required that the students______ mobile phones in their school, so seldom ______ them using one.
| A．not use; will you see | B．should not use; you will see |
| C．don’t use; will you see | D．would not use; you will see |