Some researchers are finding that daydreaming may be important to ______ mental health. Daydreaming, they say, is ______ good means of relaxation.
| A．the; 不填 | B．不填 ; the | C．不填; a | D．不填; 不填 |
He smiled politely ________ Mary apologized for her drunken friends.
| A．as |
| B．if |
| C．unless |
| D．though |
—Coach，can I continue with the training?
—Sorry，you can’t________you haven’t recovered from the knee injury.
| A．until |
| B．before |
| C．as |
| D．unless |
I had hardly got to the office________my wife phoned me to go back home at once.
| A．when |
| B．than |
| C．until |
| D．after |
Please call my secretary to arrange a meeting this afternoon，or________it is convenient to you.
| A．whenever |
| B．however |
| C．whichever |
| D．wherever |
He was so deep in thought，thinking of the problem ________ he knocked into the tree without noticing it.
| A．when |
| B．while |
| C．because |
| D．that |