Scientists are convinced ___ the positive effect of laughter ____ physical and mental health．
| A．of; on | B．by; in | C．of; at | D．on; at |
He said______ his sister had passed the entrance examination of college, and______she would go to college in about 20 days.
| A．that; ／ | B．that; that | C．／; ／ | D．that; which |
Mr. Smith was so angry at all ______ Bill was doing ______ he left.
| A．that; what | B．that; that | C．which; which | D．what; that |
_______ has recently been done to provide more buses for the people, a shortage of public vehicles remains a serious problem.
| A．What | B．Though what | C．In spite of what | D．However what |
He wondered ________ his son was getting along with the experiment.
| A．when | B．what | C．how | D．which |
In 1492 Columbus and his crew arrived ______ was so-called the New World by the westerners．
| A．in what | B．in which | C．what | D．where |