The middle and high school period is a special one for children, a transition from children to adult, ______ children tend to be rebellious.
| A．when | B．where | C．that | D．of which |
The bell _______ the end of the period rang, _______ our heated discussion.
| A．indicated; interrupting | B．indicating; interrupting |
| C．indicating; interrupted | D．indicated; interrupted |
The research is so designed that, once _______, nothing can be done to change it.
| A．begins | B．having begun | C．begun | D．Beginning |
The most important thing _______ we should pay attention to is the first thing ________ I have said.
| A．which; that | B．that; which | C．that; that | D．which; which |
_____, the great mother, in order to save her sick child, kept waiting for four hours in the heavy snow.
| A．It depends | B．Take it easy | C．Believe it or not | D．It is OK |
Was it in 2002 __________ he was still at middle school __________ the boy became expert at computer?
| A．that; where | B．when; where | C．that; when | D．when; that |