I had been puzzled over the problem for over an hour without any result, ____ all at once the solution flashed across my mind.

A. while                             B. when 　　                    C. then 　　            D. as

Can’t we just live in today, _______ the worries of tomorrow or the regrets of the past?

A. free from             B. aware of                     C. sure of          D. tired from

As is natural, a man as old as he ____ be very forgetful.

　A. can 　　　　                   B. should 　　　　        C. would 　　　　D. must

 It is ____ you deal with difficulties that shows ____ you are really like.

　A. what; what                       B. how; what 　　          C. how; that 　　  D. which; how

 ____ only 20 minutes to go before the train left, I felt uneasy in the taxi to the railway station.

　A. For 　　　　　             B.I had 　　　　            C. With 　　　　  D. As

The time he has devoted in the past years ____ the disabled is now considered ____ of great value.

         A. to help; being     B. to helping; to be  C. to help; to be       D. helping; /

 ---Cliff, I lost your ball at school. I suppose I should pay for it.

　 ---Oh.____. It was just an old ball anyway.

　 A. Take it easy                      B. By no means 　　      C. You got it 　　   D. Forget it

While watching TV, ____.

         A. the doorbell rang         B. the doorbell rings        

         C. we heard the doorbell ring D. we heard the doorbell rings

If you go to Xi’ an, you’ll find the palaces more magnificent than commonly ____.

         A. supposing    B. supposed     C. to suppose  D. suppose

 Imagine life as a game ____ you are playing with five balls. You name them---work, family, health, friends and spirit.

         A. where            B. that      C. as         D. which