The boss____________ the worker how to do it, or the accident couldn't have happened.
| A．can't have told | B．ought to tell |
| C．could have told | D．mustn't have told |
----I’m going to the United States.
---- How long ____you ____in the States ？
| A．are; stayed | B．are; staying |
| C．have; stayed | D．did; stay |
He often helps the students _________he thinks are not quick at their studies.
| A．whom | B．whose | C．when | D．who |
This painting of his had been ____________ by some experts of the world.
| A．high thought of | B．well thought of |
| C．highly thought | D．good thought |
My sister has become a nurse, ___________ was what she wanted to be.
| A．who | B．that | C．which | D．She |
As I know, there is _____ person in this neighborhood.
| A．no such a | B．no a |
| C．not such | D．no such |