_______the Internet is bridging the distance between people, it may also be breaking some home or will cause other family problems.
| A．When | B．While | C．If | D．As |
The teacher ___________his students to work hard.
| A．urged | B．suggested | C．demaded | D．couraged |
After the age of 50 people often _____________ their individual ambitions.
| A．desert | B．give in | C．give away | D．abandon |
He is a key ____________ in the murder so we must protect him from all kinds of danger.
| A．witch | B．watcher | C．wizard | D．witness |
Russia is _________ on the north of China.
| A．bounded | B．bound | C．boundary | D．lied |
Lately some scientists are experimenting ___________ white mice to ____________ this kind of medicine.
| A．on,try on | B．with, test on | C．on ,test out | D．with,carry out |