Scientists are convinced _____the positive effect of laughter _____physical and mental health．
| A．of ;on | B．by; in | C．of ; at | D．on ;at |
—What do you think of your step-mother?
—There are some things that are not easy to______, but on the whole she is a good mother.
| A．come up with | B．catch up with | C．break up with | D．put up with |
John rushed out in a hurry, ____ the door ____.
| A．leaving ; unlocking | B．left; unlocked | C．leaving; unlocked | D．left; unlocking |
—Jack, _____ you behave yourself? You're no longer a kid．
—Sorry, Daddy．It won't happen again．
| A．mustn't | B．can't | C．should | D．would |
Can you tell me ___ which you based your calculation __ detail ?
| A．on; in | B．on; at | C．about ;in | D．about; for |
After looking at many new cars, I found ______ which I would accept just as suitable．
| A．it | B．this | C．that | D．one |