一般灭火器的灭火原理是( )。

A．隔绝氧气
B．降低温度
C．增加湿度
D．制造泡沫

In the New York street a small truck hit a big tree. The truck was full of glasses and they were all (41) now. The driver came out of the truck and looked at the broken glasses. He was very (42) . And people in the street were (43) for him.
Then an old man walked to the driver, looked at him for a few (44) and said, "My poor boy, I think you must (45) a lot for it."
"Yes, "was the bad answer.
"Well, "said the old man," hold out your (46) . Here’s some money for you, and I hope all the people around here will give you (47) ,too. "With these words, he walked away.
The driver held out his hat and over a hundred people came and put their money in it. At last the driver (48) a bag and put all the (49) in. Then he looked at the people and said, "Thank you very much. I’m working for that old man and all these (50) are made in his factory. \

[A] a helping hand [B] glasses [C] a truck