问题
单项选择题
止回阀具有（）关闭阀门的功能，它能在管路中使流体只能向一个方向流动，不允许反向流动。
A.自动
B.半自动
C.手动
D.气动
答案
参考答案：A
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止回阀具有（）关闭阀门的功能，它能在管路中使流体只能向一个方向流动，不允许反向流动。
A.自动
B.半自动
C.手动
D.气动
参考答案：A
| 阅读理解。 | ||||
| ||||
| 1. The apartment with furniture is for _________ specially. | ||||
| A. families B. students C. tourists | ||||
| 2. The main cause of eyesight problems in School A is _________. | ||||
| A. reading in bed B. using computers C. watching TV | ||||
| 3. The number of the boys who had mobile phones in School B _________ from 2005 to 2007. | ||||
| A. increased rapidly B. grew slowly C. remained the same | ||||
| 4. In 2007, _________ girls had mobile phones in School B. | ||||
| A. 8 B. 14 C. 20 | ||||
| 5. If Jim has a cold, he should take _________. | ||||
| A. three cold pills each time B. the cold pills before meals C. the cold pills 3 times a day |
