We want such materials ________ can bear high temperature and pressure.
| A．that | B．as | C．what | D．which |
As we all know, he never ______.
| A．smoking | B．smoked |
| C．smokes | D．to smoke |
We ______ to clean the blackboard every day.
| A．take turn | B．in turn |
| C．by turns | D．take turns |
The old man is ______ under the tree and ______ a paper.
| A．sitting, reading | B．sleeping, looking |
| C．sleeping, reading | D．sitting, looking |
-Can you stand ______ in that way?
- Absolutely not.
| A．to tell a lie | B．to be told a lie |
| C．telling a lie | D．be telling a lie |
Don't forget ______ the light when you leave the office.
| A．switching over | B．to turn on |
| C．to switch on | D．to switch off |