NH4NO3受热后易分解，但放出的气体无害。

一些食品常用袋装生石灰做干燥剂．生石灰是（　　）

A．酸

B．碱

C．盐

D．氧化物

阅读短文，判断正(T)误(F)。

     Hello, everyone! This is my new school. Look at the tall building. There are fifty-two classes in it.

There is a computer and a television in a classroom. 

    The library is next to the tall building. There are many books in it. We like reading story books there.

The gym is behind the library. We often play games and swim there. The offices are next to the gym. 

There are thirty offices in that building. There are three science labs in it,  too. The offices are in front of

the dining hall. 

     My new school is very big and I like it.

(     )1. My new school has fifty-two classes.

(     )2. The library is next to the offices.

(     )3. We like reading storybooks in the classroom.

(     )4. There are two science labs in the school.

( )5. The dining hall is behind the offices.

钾离子通道阻滞剂（）

A.奎尼丁

B.美西律

C.维拉帕米

D.普罗帕酮

E.胺碘酮

在燃气轮机启动、停机及停机后的盘车过程中一旦发生失去交流电源的情况下，辅助润滑油泵即退出运行，燃气轮机机组轴承的冷却、润滑将由（）来提供，维持机组正常的润滑油供应。

A、主润滑油泵

B、辅助润滑油泵

C、紧急润滑油泵

D、紧急密封油泵

全部损失是指运输中整批货物或不可分割的一批货物的全部损失。