Scientists are convinced ______ the positive effect of laughter ______ physical and mental health.
| A．of; at | B．by; in | C．of; on | D．on; at |
Look out! Don’t get close to the house, ______ the roof is under repair．
| A．whose | B．which | C．of which | D．that |
Quite a few people like traveling, for it can increase their knowledge and broaden their _____．
| A．features | B．horizons | C．heritage | D．reservations |
________, a man who espresses himself effectively is sure to succeed more rapidly than a man whose command of language is poor．
| A．To be equal to other things | B．Other things to be equal |
| C．Were other things equal | D．Other things being equal |
_____ is obviously right is to give all children equal opportunities to develop their special gift．
| A．Which | B．What | C．That | D．It |
Take care not to get your shoes ______ in mud．
| A．wet or covered | B．to be wet or covered |
| C．to be wet or covered | D．wet or be covered |