He was about halfway through his meal ____ a familiar voice came to his ears.

A.why                        B. where                            C. when                             D. while

 ____ outer space will surely cost a lot of money and efforts.

A.Exploring                 B. Sending                  C. Enjoying                 D. Watching

 The flying saucer ____ and disappeared before they could see clearly.

A.lifted off                  B. carried off                      C. put off                    D. turned off

 They are twins but they have quite different ____.

A.common                  B. value                      C. reward                   D. character

 The processing secret of the new product was ____ by the reporter who had little sense of keeping the secret.

A.let into                     B. let out                     C. let down                 D. let be

My uncle is very ____ and he is always ready to help those who are in trouble.

A. cruel B. generous 　　　　　　　 C. smart D. sensitive

You'd better ____ in an emergency.

A. keep still B. keep calm C. keep silent D. keep quiet

 He was about to tell me the secret ____ someone patted him on the shoulder. 

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

 She had just finished her homework _____ her mother asked her to practice playing the piano yesterday.

A. when                             B. while                       C. after                        D. since

Peter won't drive us to the station. He has ____ to take us all.

A.a very small car B. too small a car C. a too small car D. such a small car