It is necessary to explain your theory _____, otherwise the audience won't make sense of what you are trying to get across.
| A．on purpose | B．at length | C．at random | D． on average |
I don’t know whether you happen_______, but I’m going to study in the U.S.A. this September.
A. to be heard B. to be hearing
C. to hear D. to have heard
The flu is believed _______ by viruses that like to reproduce in the cells inside the human nose and throat.
| A．causing | B．being caused |
| C．to be caused | D．be have caused |
We often provide our children with toys,footballs or basketballs, _______ that all children like these things.
| A．thinking | B．think |
| C．to think | D．thought |
The Olympic mascots are the Olympic flame, the fish, the panda, the Tibetan antelope and the swallow, _______ a close group of friends.
| A．to represent | B．representing |
| C．represented | D．represent |
I send you 100 dollars today,the rest _______ in a year.
| A．follows | B．followed |
| C．to follow | D．being followed |