阅读理解。

     I am Cheng Hai. This is Mr. Read. He is English. He isn't an English teacher. But Mrs. Read is an

English teacher. Mrs. Read and I are both English teachers. We are good friends. We work in the No.4

Middle School. It' s a nice school.

1. My name is _____.

A. Mr. Read

B. Cheng Hai

C. Mrs. Read

D. you can't know

2. _____ isn't an English teacher. 

A. Cheng Hai

B. Mrs. Read

C. Mr. Read

D. A, B and C

3. Cheng Hai is _____.

A. Mr. Read' s teacher

B. Mrs. Read' s teacher

C. English

D. a teacher of English

4. Mr. Read is _____.

A. English

B. not English

C. Cheng Hai' s teacher

D. Chinese

5. _____ are good friends.

A. Mr. Read and Mrs. Read

B. Mr. Read and I

C. Mrs. Read and I

D. All of us

有一条D219×6mm的20号无缝钢管，输送介质温度为250℃，安装时环境温度为10℃，两固定支架间距为30m，试计算该管段的热伸长量和热应力以及固定支架所受到的推力。