阅读理解。 To extinguish (熄灭) different kind

题目：

阅读理解。

     To extinguish (熄灭) different kinds of fires, several types of fire extinguishers have been invented.

They must be ready for immediate use when fire breaks out. Most portable (手提式的) kinds operate

for less than a minute, so they are useful only on small fires. The law requires ships, trains, buses and

planes to carry extinguishers.

     Since fuel, oxygen (氧气) and heat must be present in order for fire to exist, one or more of these

things must be removed or reduced to extinguish a fire. If the heat is reduced by cooling the material

below a certain temperature, the fire goes out. The cooling method is the most common way to put out

a fire. Water is the best cooling material because it is low in cost and easy to get.

     Another method of extinguishing fire is by cutting off the oxygen. This is usually done by covering

the fire with sand, steam or some other things. A blanket may be used do cover a small fire.

     A third method is called separation, which includes removing the fuel, or material easy to burn, from

a fire, so that it can find no fuel.

     The method that is used to put out a fire depends upon the type of fire. Fires have been grouped in

three classes. Fires in wood, paper, cloth and the like are called Class A fires. These materials usually help

keep the fire on. Such fires can be stopped most readily by cooling with water.

1. If a fire breaks out on a bus, which of the follow should be ready there for you to use?

A. Sand

B. Water

C. A blanket.

D. An extinguisher.

2. To cover a small piece of burning wood with a basin in order to stop the fire is an example of _____.

A. separating the fire

B. reducing the heat

C. removing the fuel

D. cutting off the oxygen

3. In choosing how to put out a fire, we should first be clear about _____.

A. when it breaks out

B. how it comes about

C. what kind it is

D. where it takes place

4. What would the author probably discuss in the paragraph that follows?

A. Another class of fires

B. Another type of extinguishers

C. How fires break out.

D. How fires can be prevented.