______ to too much sunlight, as is generally considered, will add to the potential of catching skin cancer.
| A．Being exposed | B．Exposed | C．Exposing | D．To expose |
I had just got up and was about to cook my breakfast__________ the telephone rang, but it was hung up __________ I could answer it.
| A．while ； when |
| B．when ； as |
| C．as；after |
| D．when；before |
Swimmers must be very strong in order to build up speed because of the high resistance (阻力)of the water. Runners,__________, must struggle against the heavy resistance of the air and ground.
| A．generally |
| B．similarly |
| C．naturally |
| D．probably |
They're not playing baseball today __________ the rain.
| A．because |
| B．as |
| C．since |
| D．because of |
In some places women are expected to earn money __________ men work at home and raise their children.
| A．but |
| B．while |
| C．because |
| D．though |
Joe, don't __________ now ； you're improving all the time. It won't be long __________ you can speak English well.
| A．give in ； until |
| B．give up ； before |
| C．give in ； when |
| D．give up ； after |