传动滚筒、尾部滚筒轴中心线与机身中心线不垂直，能导致跑偏。

下列各句中，没有错别字的一项是[ ]

A．今年以来，一方面是大量待业人员寻工无着，另一方面是沿海地区许多企业招聘不到足够的人员，“就业难”与“用工荒”折射出我国产业转型时期的“就业之觞”。

B．春暖花开，万物复苏，但恼人的“春季综合征”也接踵而至，虚弱无力、心情阴郁、对什么都提不起兴趣，这些都是其具体表现。

C．又是地震，又是灾难，近期全球地震频烦，无数人在倾刻之间失去生命，灾难带来的断壁残垣以及残疾、孤儿现象让人心痛。

D．在全国各大城市房价飙涨的背景下，房价越来越成为中低收入人群无法逾跃的屏障，拥有自己的房子也越来越成为难以企及的梦想。

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.

独立前拉丁美洲人民的主要敌人，除西班牙殖民者以外，还有[ ]

A．英国人

B．俄国人

C．美国人

D．葡萄牙人

上尿路结石是指

A．肾结石

B．输尿管结石

C．膀胱结石

D．输尿管和膀胱结石

E．肾和输尿管结石

惯性导航的英文缩写（），磁力计的英文缩写（）。