问题 多项选择题

下列传热表述正确的是()

A.焦炉立火道中火焰和热废气的热量通过对流和辐射向炉墙传递

B.炭化室炉墙的传热属不稳定的热传导

C.炭化室煤料在整个结焦时间内为不稳定的平壁热传导

D.蓄热室中的格子砖是热量的传递者

答案

参考答案:A, B, C, D

阅读理解

阅读理解。

     Do you want to say that what you think in a letter to Jimmy Carter, president of the United States? You will

get an answer from him-written in ink, not typed-after only a few days. Jimmy Carter gets about 4,000 letters

every week. He answers every letter on special White House paper. But he doesn't need a lot of time for it. In

fact, he only gives 20 minutes a week to look at his private letters. He has the most modern computer in the

world to help him. It costs about US$1,200,000.

     This computer has its own rooms on the first floor of the White House: It has a lot of electronic pens (电

子笔) and they write like the President writes, in his favourite light blue ink. Each letter takes less than a second

to write. A White House official said,"It's not important that the letters come from a computer. Each letter says what the president wants to say."

1. What is the passage mainly about?

A. President of the United States

B. The letters of president

C. President's computer

D. How president writes letters

2. How long does the computer spend in writing a letter?

A. A minute.

B. An hour.

C. A second

D. Less than a second.

3. How long does he spend in reading his private letters every week?

A. Twenty minutes

B. Twenty seconds

C. Ten hours

D. Half an hour

4. The computer cay say ______ in its letters.

A. the same words

B. the different words

C. the words that president wants to say

D. the simple words

5. The computer is very ______.

A. clever

B. friendly

C. cheap

D. useless

单项选择题