She________have been to your house. She doesn't know your address.
| A．mustn't |
| B．shouldn't |
| C．might not |
| D．can't |
At the meeting they discussed three dif-ferent_______to the study of mathematics。
| A．approaches | B．means | C．methods | D．ways |
T0 make members 0f a team performbetter,the trainer first of all has to know their_______and weaknesses。
| A．strengths |
| B．benefits |
| C．techniques |
| D．values |
When Jane began to take swimminglessons,her main_______was the fear of water。
| A．evidence | B．crisis |
| C．obstacle | D．danger |
Finding information in today’s world is easy．The_______is how you can tell if the information you get is useful or not。
| A．ability | B．eompetition | C．challenge | D．knowledge |
It is no______arguing with Bill because he will never change his mind。
| A．use | B．help | C．time | D．way |