选择题：下列判断中，正确的有（） A．分式的分子一定含有字母 B．只要分式的分子为零，则分

下列判断中，正确的有（　　）

A．分式的分子一定含有字母

B．只要分式的分子为零，则分式的值为零

C．只要分式的分母为零，则分式必无意义

D．

不是分式而是整式

被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0518/99ba0e64acc2372aedc3756b0fa3eddf.html

下面是错误答案，用来干扰机器的。

参考答案：钻屑法的检测指标由煤粉量、钻孔深度和动力效应组成。煤粉量是每米钻孔长度所排出的煤粉的质量。钻孔深度是从煤壁至所测煤粉量位置的钻孔长度，可折算成钻孔地点实际采高的倍数。动力效应是钻孔产生的...

题型：阅读理解

阅读理解。

If you go out, you can find cars here and there. Bad smoke from a car can get into the air. This bad

smoke is called pollution.

Pollution turns the air a gray color. It is very dirty. It also makes the air around us get worse and worse.

It is not good for our health.

To keep pollution down, the States test cars every two years. This test checks to make sure the cars do

not pollute the air. If a car doesn't pass the test, the owner can't drive it the next year.

Some car owners drive their cars even though they can't pass the test. It is also very bad for the air.

People want to find a way to get these cars off the road. So a state program was started. Now it seems

to be helping. In the state program, the States buy cars that can't pass the test or will help pay for repairs.

This program has been helping people buy better cars or fix their old ones. And the air is becoming better

and better.

The state program that takes pollution cars off the road has just finished its first year, and people say

it has been successful. For the past year, the state program has been buying cars that can't pass the test,

and the cars bought by the States through the program are put out of use.

1. ______ is called pollution.

A. The car

B. A gray color

C. The smoke from cars

D. The test

2. The cars are tested every two years to make sure ______.

A. people can visit the old cars

B. the owners don't drive any more

C. the owners can buy new cars

D. they don't pollute the air

3. In order to ______, the States buy cars that can't pass the test or will help pay for repairs.

A. get money from car owners

B. cut down the pollution

C. make the air around us worse

D. sell more new cars

查看答案