As a physics teacher, Mr. Chen devoted himself to teaching and researching, which earned him a good ______ in his field.
| A．reputation | B．expectation |
| C．impression | D．Knowledge |
I would appreciate it________you call back this afternoon for the doctor's appointment.
| A．until |
| B．if |
| C．when |
| D．that |
________much advice I gave him, he did exactly what he wanted to do.
| A．How |
| B．Whatever |
| C．However |
| D．No matter |
The research is so designed that once________nothing can be done to change it.
| A．begins |
| B．having begun |
| C．beginning |
| D．begun |
Visitors________not to touch the exhibits.
| A．will request |
| B．request |
| C．are requesting |
| D．are requested |
It is known to all that________you exercise regularly, you won't keep good health.
| A．unless |
| B．whenever |
| C．although |
| D．if |