天然气的主要成分是甲烷(CH4),它是一种“清洁能源”.甲烷在空气中完全燃烧生成

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问题:

天然气的主要成分是甲烷(CH4),它是一种“清洁能源”.甲烷在空气中完全燃烧生成二氧化碳和水,燃烧32g甲烷,可释放多少克二氧化碳?

考点:化学反应方程式的计算
题型:问答题

阅读理解。

     Mr Smith has about 2000 clocks in his house. He collects them from his childhood(童年). He puts

these clocks everywhere: on the tables and chairs, in the old car, and even under his bed. But Mrs Smith

doesn’t like these clocks at all. She has to (不得不) clean all the clocks every day. She has to listen to the strike(敲)of the clocks every minute. Even though(即使)with so many clocks, she can't tell the right time!

1. When does Mr Smith collect these clocks?

A. When he is a child.      

B. In 2000.    

C. After school.    

D. In the evening.

2. Where deos Mr Smith put his clocks?

A. On the tables and chairs.  

B. In the drawers.  

C. Under the bed.  

D. Both A and C.

3. What does Mrs Smith have to do every day?

A. Tell the time.    

B. Clean the clocks.    

C. Listen to the music.    

D. Go to work.

4. Why can’t Mrs Smith tell the right time?

A. Because she doesn’t have a clock.

B. Because her clocks are brocken.

C. Because different clocks have different times.

D. Because she can’t see the clocks.

5. How many clocks does Mr Smith have?

A. About 20      

B. About 200.    

C. About 2,000.    

D. About 20,000

题型:问答题

通风机电动机()运转时,允许先停机后汇报。

题型:问答题

已知x2+4x-1=0,求代数式2x4+8x3-4x2-8x+1的值.

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女性,32岁,已婚。肛周及外生殖器丘疹、 * * 状赘生物,醋酸白试脸阳性。

导致该病病毒感染是()

A.麻疹病毒

B.单纯疱疹病毒

C.水痘-带状疱疹病毒

D.人类 * * 瘤病毒

E.冠状病毒

题型:问答题

右图为鸟卵的结构模式图,请判断下列说法不正确的是(     )

A.鸟的胚胎发育是从⑤开始的

B.⑥能为胚胎发育提供氧气

C.图中③④⑦构成一个完整的卵细胞

D.鸟卵离开母体即停止发育的原因是外界温度太低

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