问题 问答题 简答题

如何保证内燃机的正常润滑?

答案

参考答案:

(1)足够的可以促使油楔形成的收敛表面;

(2)足够的油量;

(3)适当的配合间隙;

(4)足够高的运动速度;

(5)适当的润滑油粘度;

(6)防止负荷过大。

阅读理解

阅读理解。

     A neighbor of mine, while visiting his mother in Boston, took her to a shoe store to buy a new pair of

shoes. While she was trying on different styles (款式), my neighbor took the manager aside. "When she

picks out a pair that she likes," he said, "just tell her that the price is 12 dollars. I'll pay the regular (正常的)

price. I don't care how much it is."

     The following week, my neighbor was walking by the shoe store and the manager recognized (认出) him

and called him in.

      "What's the problem?" asked my neighbor as he entered the store.

      "Wasn't my check any good?"

      "That's not it," answered the manager," The problem is that your mother is bringing all her friends in for

those 12-dollar shoes!"

1. My neighbor went to Boston ________.

A. to buy shoes for his mother

B. to see his mother

C. to pay for the shoes he had bought for his mother

D. to see the manager of the shoe store

2. The regular price my neighbor had paid must be _______.

A. 12 dollars

B. lower than 12 dollars

C. higher than 12 dollars

D. unknown to himself at all

3. It seems very probable that my neighbor wanted to _______.

A. please his mother

B. cheat his mother

C. cheat the manager

D. please his mother's friends

4. The manager called my neighbor in when he saw him because______.

A. he didn't have enough shoes for his customers (顾客)

B. my neighbor's mother had taken a wrong pair of shoes

C. there was something wrong with his check

D. he found it hard to satisfy his customers

5. What do we know about the character (个性) of my neighbor's mother?

A. She would like to buy expensive things.

B. She would like to buy cheap things.

C. She would like to help others when they're in trouble.

D. She would like to have her son pay for her shopping.

单项选择题