I failed in the examination last term and only then ____the importance of study.
| A．I realized | B．I had realized | C．had I realized | D．did I realize |
All passengers ____, please fasten your seat belts and remain seated ____the plane is landing．
| A．on board; until | B．abroad; since | C．on the board; before | D．aboard; when |
He ____ busy then; otherwise, I believe, he would have given you a hand．
| A．had been | B．were | C．must be | D．was |
It is not like Mr．Smith, who is a gentleman, _____his wife so rudely．
| A．to treat | B．treating | C．should treat | D．treated |
As the saying _______, _______ who laughs last laughs best．
| A．says; who | B．goes; he | C．goes; who | D．puts; one |
An increasing number of people enjoy sun-bathing, but experts warn that too much ________of the body to strong sunlight is harmful．
| A．access | B．exposure | C．resistance | D．touch |