Many teenagers say that _____ they have a lot of friends, they really have no best friend.
| A．when | B．while | C．if | D．because |
His younger sister may already be in high school now, in ________ case this picture book is too childish for her.
| A．that | B．which |
| C．whose | D．what |
It is by no means clear ________ the president can do something to end the strike.
| A．whether | B．which |
| C．that | D．what |
Good shoes, clothes and a backpack are the basic ________ you need for your hiking.
| A．equipment | B．instruments |
| C．tools | D．models |
The Australian boy has a good ________ of Chinese and can express himself freely in it.
| A．power | B．command |
| C．demand | D．usage |
—How can I use the equipment?
—Well, just refer to the ________.
| A．directions | B．explanations |
| C．expressions | D．introductions |