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 |
--So you know Catherine?
---Yes, it was last week_____ she came to visit my roommate Jane.
| A．that | B．when | C．since | D．before |
________there are a large number of chemical factories, the air is likely to be polluted.
| A．Where | B．That | C．Though | D．As |
They weighed the advantages of the operation ______ all the possible risks involved over and over again.
| A．within | B．except | C．behind | D．against |
The young man has been trying everything in his power to please the director, ______ to get a role in the play.
| A．hoped | B．hoping | C．to hope | D．having hoped |
Sometimes we just can’t understand why so many people fail to realize that wealth does not ______ bring happiness?
| A．consequently | B．automatically | C．necessarily | D．particularly |