关系模型的完整性规则是对关系的某种约束条件，包括实体完整性、______和自定义完整

风心病最多见的心律失常是（）

A.室性早搏

B.房性早搏

C.心房颤动

D.阵发性室上速

E.窦性心动过速

重10N的长方体木块沿斜面匀速下滑，图所示是某同学所画的木块受重力的图示，其中错误的是：

（1）_____________________________；

（2）_____________________________ 。

“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

男性，30岁。车祸外伤1小时，左颞部着力，当时有短暂昏迷，对受伤情况不能回忆。查体：神志清楚，神经系统无阳性体征。

初步诊断为（）

A.脑震荡

B.脑挫裂伤

C.脑供血不足

D.脑水肿

E.脑疝

下列关于态生系统说法，正确的是（）

A.生物群落与其生存环境之间不听进行物质循环和能量交换构成生态系统

B.生态系统中生物脱离了环境难以生存

C.生态系统中所有生物均能只是其所在的自然环境

D.生物对其环境影响极其微弱