单词拼写。

1. The ___________ (气氛)changed as he walked in.

2. The professor has brought in a good ____________ (系统)of teaching languages from abroad.

3. He was very ___________ (粗暴的)when he got drunk.

4. They laid eggs too and __________ (生存)on the earth for more than 140 million years.

5. A friend in need is a friend ___________(真正地).

6. He addressed the ___________ (信封)and put a letter in it.

7. His excuse for being late was totally ___________ (不可信的).

8. After three hours of waiting for the train ,our ___________( 耐心)was finally exhausted.

9. The boy shows great ____________ (好奇心)about animals.

10. The song ___________ (使想起)me of the days we spent together several years ago.

发动机空中起动与地面起动的主要区别是：（）

A.不用起动机，用A.PU气源带动发动机转子

B.不用起动机，用A.PU电源带动发动机转子

C.不用起动机，用进口冲压空气带动发动机转子

D.用起动机，由A.PU气源带动发动机转子