When he knocked at the door, my mother was busy ____ supper.
| A．preparing for | B．in preparing |
| C．to prepare for | D．to prepare |
When ____ to danger and conflict, men tend to increase blood pressure, ____ nervous or anxious.
| A．exposed; felt | B．exposing; felt |
| C．exposed; feeling | D．exposing; feeling |
It is believed that _____ European scientist invented _______.
| A．an; a television | B．a; a television |
| C．an; the television | D．a; the television |
I don’t think David could have done such a stupid thing last night, ____?
| A．did he | B．didn’t he |
| C．do I | D．don’t I |
We had tried everything to improve their living conditions,but it made little .
| A．good | B．use |
| C．result | D．difference |
He is my father and I know he will forgive me for _______ I have done.
| A．whatever | B．no matter what |
| C．no matter how | D．whichever |