题目内容
13．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 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．
25．If a fire breaks out on a bus，which of the follow should be ready there for you to use？D
A．Sand B．Water C．A blanket．D．An extinguisher．
26．To cover a small piece of burning wood with a basin in order to stop the fire is an example ofA．
A．cutting off the oxygen B．reducing the heat
C．removing the fuel D．separating the fire
27．In choosing how to put out a fire，we should first be clear aboutB．
A．when it breaks out B．what kind it is
C．how it comes about D．where it takes place
28．What would the author probably discuss in the paragraph that follows？B
A．Another type of extinguishers
B．Another class of fires
C．How fires break out．
D．How fires can be prevented．
分析 本文为科普类说明文；文章主要介绍了如何灭火；文章介绍了火存在的三个要素：燃料、氧气和热量；如果其中一个或几个因素被去除，火就会熄灭；所以灭火由相应的三种方法：冷却是最常见的方法，水是最常见的冷却的材料；切断氧气是第二种方法，通常是在火上覆盖沙子等物品；第三种是分离法，即去除容易燃烧的材料；用什么方法灭火取决于火的类型．
解答 25．答案是D．细节理解题；根据第一段最后一句"The law requires ships，trains buses and planes to carry extinguishers（法律要求船上、火车上、公共汽车和飞机上必须携带灭火器．）"说明在公共汽车上有灭火器，公共汽车上着火应该用灭火器．
26．答案是A．细节理解题；根据第三段"Another method of extinguishing fire is by cutting the oxygen．This is usually done by covering the fire with sand，steam or some other things（另一种灭火的方法是切断氧气．这通常是用沙子、蒸汽或其它东西覆盖在火上）"判断，用脸盆盖上烧着的木头显然是截断氧气的方法．
27．答案是B．细节理解题；根据最后一段的第一句"The method that is used to put out a fire depends upon the type of fire．（用来灭火的方法取决于火的类型）"可知要想判断用什么方法，首先要弄清着火的类型，所以选B．
28．答案是B．推断题；最后一段描述了"Fires have been grouped in three classes．（火分三种类型）"然后讲述了第一种，所以后面很可能描述另外两种．所以选B．
点评 阅读要整体理解文章，在做细节题时根据题干定位细节，在语境中正确理解原句，然后对照选项做出合理的判断；必要的时候要进行推理，透过句子表面看作者的真正意图．如果是主旨大意的判断要把握文章整体，避免以偏概全．
