Accustomed to___ the steep mountains,he had no difficulty reaching the top
| A．climbing |
| B．climb |
| C．having climbed |
| D．have climbed |
If you really have to leave during the meeting, you’d better leave _________ the back door.
| A．for | B．by |
| C．across | D．out |
Fred entered without knocking and, very out of breath, sank _________ a chair.
| A．on | B．off |
| C．into | D．to |
The open-air celebration has been put off __________ the bad weather.
| A．in case of | B．in spite of |
| C．instead of | D．because of |
__________ fire, all exits must be kept clear.
| A．In place of | B．Instead of |
| C．In case of | D．In spite of |
Some students often listen to music __________ classes to refresh themselves.
| A．between | B．among |
| C．over | D．during |