Because the shop _______, all the T-shirts are sold at half price.
| A．has closed down | B．closed down |
| C．is closing down | D．had closed down |
29. The key ____ English well is to read more when ____.
| A．to learn, possible | B．of learning, possibly |
| C．of learning, was possible | D．to learning, possible |
34. The biggest problem for most plants, which _______ just get up and run away when threatened, is that animals like to eat them.
| A．shan’t | B．can’t | C．needn’t | D．mustn’t |
33. ---How long have you been in this office?
---Just a few minutes. My cousins _______ here together with me.
| A．have walked | B．had walked | C．walked | D．have been walking |
31. ----Who are you waiting for?
---__________ the man wounded in the left leg.
| A．The doctor will operate on | B．The nurse to be looked after |
| C．The doctor to operate on | D．His brother got |
29. The government has taken some measures to solve the shortages of electricity, but it may be some time _______ the situation improves.
| A．since | B．when | C．unless | D．before |