问题 单项选择题

窒息灭火的灭火机理是()。

A.降低温度

B.降低燃点

C.减少可燃物

D.降低氧浓度

答案

参考答案:D

解析:可燃物的燃烧是氧化作用,需要在最低氧浓度以上才能进行,低于最低氧浓度,燃烧不能进行,火灾即被扑灭。一般氧浓度低于15%时,就不能维持燃烧。在着火场所内,可以通过灌注不燃气体,如二氧化碳、氮气、蒸汽等,来降低空间的氧浓度,从而达到窒息灭火。因此,本题的正确答案是D。

阅读理解

阅读理解。

     On some level, I always knew that I wanted to be a doctor-at least from the age of eight or ten years old,

anyway.

     Although my father wasn't a doctor, he made his own brand of "house calls. I followed him as he brought

a plate of my mother's home cooking to an elderly man named Frank on all major holidays and when Frank

was sick. As far as I know, their only connection was that Frank was an occasional customer at Dad's small

gas station. Frank's home was a two-room house on the rough side of town with an old front porch (门廊)

where you could fall if you weren't careful. Frank had no relatives and as far as I could tell, no other visitors

either. Through his attitude of caring, my father was teaching me to be a doctor, although neither of us knew

it at the time.

     When I was 13, my father developed lung cancer. He brought home a diagram the doctor had drawn

showing where his cancer was and told me that he was going to die. He asked me to take care of my mother

when he was gone. I was an only child. He said he loved me on the night when he died.

     When you're 13 and your father dies, you have some choices to make. You can use the situation as an

excuse for letting your actions and grades go down, or you can honor his memory and try to do something

positive with yourself. I focused my energy on my schoolwork and my goal of becoming a doctor.

1. What was the father's "own brand of 'house calls'"?

A. His treatment for Frank's serious illness.

B. Being kind to Frank.

C. His attitude towards the author.

D. His wish that his son would be a doctor.

2. The author did something to realize his dream to be a doctor when _____.

A. Father helped Frank regularly

B. Father developed lung cancer

C. Father asked him / her to take care of Mother

D. Father died

3. What influence did his father's death have on the author?

A. The author began to think seriously about his career.

B. The author was too sorrowful to go on studying.

C. The author used the situation as an excuse to quit school.

D. The author worked harder to achieve his goal of becoming a doctor.

4. Which of the following is TRUE according to the passage?

A. Father taught the author how to be a doctor by making house calls on Frank.

B. In return for Father's help, Frank usually came up at his gas station.

C. The author had no sisters or brothers.

D. The author was deeply influenced by Father's doctor who treated his cancer.

5. What's the best title for the passage?

A. What Made Father Respectable

B. What Led Me to Be a Doctor

C. How to Help Strangers

D. How to Deal with Death

名词解释