问题 选择题

污水处理池经常有打气装置,使水翻腾.这样做是为了(  )

A.让污水得到阳光充分照射,杀死其中的细菌

B.做喷泉的效果,让工厂更美观

C.让其中的细菌得到更多空气,更好地分解水中的有机物

D.让其中的臭气充分散发

答案

在生活污水和工业废水中有很多有机物,可以被为细菌分解、利用,在有氧的环境中,一些细菌把这些有机物质分解,产生二氧化碳和水,达到净化污水的目的,污水处理池经常有打气装置,使水翻腾,是为了其中的细菌得到更多空气,利于细菌的生长、繁殖和发酵,更好地分解水中的有机物.可见C符合题意.

故选:C

多项选择题
阅读理解

“Dr.Papaderos,what is the meaning of life?”

The usual laughter followed,and people stirred(骚动)to go.Papaderos held up his hand and stilled the room and looked at me for a long time,asking with his eyes if I was serious and seeing from my eyes that I was.

“I will,answer your question.”

Taking his wallet out of his hip pocket,he fished into a leather billfold and brought out a very small round mirror,about the size of a quarter.And what he said went like this:

“When I was a small child,during the war,we were very poor and we lived in a remote village.One day,on the road,I found the broken pieces of a mirror.A German motorcycle had been wrecked in that place.

I tried to find all the pieces and put them together,but it was not possible,so I kept only the largest piece.This one,and,by scratching it on a stone.I made it round. I began to play with it as a toy and became fascinated by the fact that I could reflect light into dark places where the sun would never shine——in deep holes and crevices(裂缝)and dark closets. It became a game for me to get light into the most inaccessible places I could find.

I kept the little mirror,and,as I went about my growing up,I would take it out in idle moments and continue the challenge of the game.As I became a man,I grew to understand that this was not just a child’s game but a metaphor for what I might do with my life.I came to understand that I am not the light or the source of light.But light——truth,understanding,knowledge——is there,and it will shine in many dark places only if I reflect it.

I am a fragment(碎片)of a mirror whose whole design and shape l do not know.Nevertheless,with what I have I can reflect light into the dark places of this world——into the black places in the hearts of men—and change some things in some people.Perhaps others may see and do likewise.This is what I am about.This is the meaning of my life.”

小题1:On hearing the author’s question,Dr.Papedotes       at first.

A.laughed at his foolishness

B.wasn’t sure of the answer

C.doubted his seriousness

D.wasn’t interested at all小题2:How did Dr.Papaderos get the small round mirror when he was a child?

A.He found it on the road and made it round.

B.A dying German soldier gave him as a present.

C.He chanced to find it in the street while playing.

D.He put the broken pieces together and made it.小题3:Why did Dr.Papaderos like the small round mirror so much as a child?

A.Because he was too poor to afford other toys.

B.Because it could shine the places where tke sun couldn’t reach.

C.Because he believed it would bring good luck to him.

D.Because it tofd him a lot about what life really meant to him.小题4:The underlined“metaphor”in the 7th paragraph most probably means       .

A.symbol

B.source

C.light

D.purpose小题5:Which of the following might be the best title for the passage?

A.A Special Game in the Childhood

B.A Broken Piece of Mirror

C.Dr.Papaderos’Experience

D.The Meaning of Life