问题 问答题

农村每年都要产生大量的秸杆,对于秸杆的利用通常有以下几种方法:

①将其作为燃料直接焚烧.

②秸杆归田.

③将秸杆打碎,与人畜粪便混合发酵产生沼气(主要含甲烷).

④将秸杆用于造纸.

(1)农业生产大量使用化肥,会改变土壤结构,破坏地力,因此提倡使用农家肥.上述4种秸杆处理方法中可以得到农家肥的是______ (填编号).

(2)写出沼气完全燃烧的化学方程式______.

从环境保护、资源利用等角度分析方法和方法,你认为最好的是______,理由是______.

(3)下列生产和使用沼气的做法可能会发生危险的是______.

A、打开沼气池,立即下去检查.

B、掏沼气池时用明火在池中照明.

C、家中沼气泄漏,立即关闭导气管开关.

D、沼气池第一次产生的沼气不经验纯,直接点燃.

答案

(1)将其作为燃料直接焚烧,不会得到农家肥,还会污染空气;秸杆归田,可以得到农家肥;将秸杆打碎,与人畜粪便混合发酵产生沼气,还能生产农家肥;将秸杆用于造纸不能得到农家肥;

(2)甲烷燃烧生成水和二氧化碳,化学方程式为:CH4+2O2

 点燃 
.
 
CO2+2H2O;从环境保护、资源利用等角度分析方法和方法,你认为最好的是将秸杆打碎,与人畜粪便混合发酵产生沼气,理由是①减轻环境污染、②废物利用(或节约资源);

(3)甲烷是可燃性气体,不纯遇明火可能会发生爆炸;所以打开沼气池,不能立即下去检查;掏沼气池时不能用明火在池中照明,以免发生爆炸;家中沼气泄漏,立即关闭导气管开关;沼气池第一次产生的沼气不经验纯,不能直接点燃,故选ABD.

故答案为:(1)②③;(2)CH4+2O2

 点燃 
.
 
CO2+2H2O;将秸杆打碎,与人畜粪便混合发酵产生沼气;①减轻环境污染、②废物利用(或节约资源);(3)ABD.

阅读理解

阅读理解。

     Do You Go To Sleep In Class?

     The "Acronym", our student newspaper, reports that most students go to sleep at 1: 30 a. m. Even if

 that's an exaggeration (夸张), it's too close to the truth. Scientists say teenagers should sleep nine hours

 each night. But that's hard to do.

     Some even "pull all-nighters". These are lazy students who have homework due (到期) the next day

  that they haven't done. In the morning they don't look healthy and you can tell who has been doing it.

     One of my classmates did a survey (调查) on the problem. She found that most kids pull all-nighters to

  finish homework, but some do it for other reasons, such as playing computer games!

     Maybe our lack of sleep is because of laziness-I think I'm a lazy student-or maybe it's because we have

  too much to do in American high schools.

     I usually go to bed around midnight. If I stayed up past 1: 30 a. m, I wouldn't get any work done. I'd be

  falling asleep at my computer. My classes begin at 7:30 a.m. I'm partly awake in my first class. By the

  second, I'm slightly tired and sleepy. By my third class, I'm sleepy. By midday I'm finally wide-awake.

 But by 3: 00 p. m., I'm slowing down again.

     Most American high schools seem to have such a problem.

     High school classes start at 7: 30 a. m., so students have to wake up one and a half hours before that to

  get ready and catch the bus. It's believed that lack of sleep can damage both grades and health.

     Some schools are paying attention. Classes in those schools start at 8:30 a. m.

1. What's the problem talked about in the passage?

    A. Many kids have too much homework to do.

    B. Many teenagers don't have enough sleep.

    C. Many children are crazy about playing computer games.

    D. Many kids are too lazy to finish their homework on time.

2. The underlined expression "pull all-nighters" most probably means _____.

    A. 开夜车

    B. 上夜班

    C. 睡懒觉

    D. 补作业

3. Which of the following is NOT a reason mentioned in the passage?

    A. Laziness.  

    B. Homework.

    C. Housework.  

    D. Computer games.

4. What's the idea suggested at the end of the passage?

    A. Later start of classes.  

    B. Less homework.

    C. Going to bed early.  

    D. Eating healthy food.

单项选择题