I _____ his telephone number. Had I known it, I would have rung him up.
| A．don’t known | B．didn’t know |
| C．hadn’t known | D．haven’t known |
Having failed my French exam,I decided to concentrate___science subjects
| A．to |
| B．upon |
| C．in |
| D．at |
The manager said to the employees at the meeting that everyone must___their attention to efficiency
| A．concertrate |
| B．focus |
| C．pay |
| D．fix |
Large quantities of cotton___shipped all over the world already.A large quantity of bamboo___used for pipes to carry water
| A．has been;are |
| B．has been;is |
| C．have been;is |
| D．have been;are |
___houses were knocked down in the earthquake
| A．A great many |
| B．The number of |
| C．A great many of |
| D．A great deal of |
___in the regulation that you should not tell other people the password of your e-mail account
| A．What is required |
| B．What requires |
| C．It is required |
| D．It requires |