----What did he say?
----He asked ______ for the book.
| A．how much did I pay |
| B．I paid how much |
| C．did I pay how much |
| D．how much I paid |
I was about to leave __________ someone knocked at the door.
| A．when |
| B．while |
| C．since |
| D．once |
I __________ what he said and I __________ him.
| A．believe ；believe in |
| B．believe in ；believe |
| C．believe ； believe |
| D．believe in ； believe in |
—I wonder why Tom left without a word.
—He __________ have had some trouble, for he looked dull.
| A．should |
| B．must |
| C．can |
| D．could |
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 |