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问题 选择题

要使已被接近饱和的硝酸铵溶液变为饱和溶液，下列方法中不正确的是（　　）

A．倒出少量溶剂

B．投入硝酸铵

C．蒸发部分水

D．适当降温

答案

A、硝酸铵溶于水，所以溶剂不能从溶液中倒出，故A错误；

B、投入硝酸铵可使接近饱和的硝酸铵溶液变为饱和溶液，故B正确；

C、蒸发部分水可使接近饱和的硝酸铵溶液变为饱和溶液，故C正确；

D、硝酸铵的溶解度随温度的降低而减小，所以降温可使接近饱和的硝酸铵溶液变为饱和溶液，故D正确．

故选：A．

阅读理解

阅读理解。选择正确的答案。

      Hello! I'm Li Ming. Look at my room. There is a desk and a chair in it. A bed is near the door. A cat

is under the desk. On the wall, there is a beautiful picture. On the floor, there is a ball. My room is small,

but (但是) it's very nice! I like my room.

1. Is this Li Ming's room? 

A. Yes, she is.

B. No, she isn't.

C. Yes, it is.

2. Where is the bed?

A. Near the window.

B. Near the door.

C. Near the chair.

3. Where is the cat?

A. On the desk.

B. Under the desk.

C. In the desk.

4. What's on the wall?

A. A beautiful picture.

B. A fan.

C. On the bed.

5. Where is the ball?

A. On the desk.

B. On the floor.

C. On the bed.
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单项选择题

带式输送机中的绞车式拉紧装置是（）装置。

A．手工操作

B．自动拉紧

C．车式拉紧

D．垂直拉紧
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