下列关于动脉的叙述中，正确的是（） A．流动脉血的血管 _爱下问搜题

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问题选择题

下列关于动脉的叙述中，正确的是（　　）

A．流动脉血的血管

B．把血液从身体各部分送回心脏的血管

C．流静脉血的血管

D．把血液从心脏输送到身体各部分的血管

答案

人体内的血管有动脉血管、静脉血管、毛细血管三种类型．其中动脉血管管壁厚，弹性最大，管腔较小，血流速度快，其功能为将血液从心脏输送到全身各处去；静脉血管管壁较薄，弹性较小，管腔大，血流速度慢，其功能为将血液从全身各处输送到心脏去；毛细血管管壁最薄，只有一层上皮细胞构成，管腔最小，只允许红细胞呈单行通过，血流速度极慢，数量最多，其功能为物质交换的场所．

故选：C

填空题

（）是使用分布在不同位置的几个传感器所测得的发射声波的时间差来确定的。

完形填空

We all have weaknesses and strengths—no matter who we are .Some get sick easily.
Some are 36 people in communication, struggling with 37 .
Sometimes weaknesses seem to outweigh (胜过)the strengths and sometimes it’s the other way around. 38 ,facing huge limitations, many people tend to 39 it as just bad luck ---but not everyone. Those who rise over their weaknesses can still manage to 40 extraordinary things.
I 41 a school prize –giving ceremony and the guest speaker was Andrew Becroft, 42 had a severe stutter (结巴 ) as a child . 43 allowing this to limit him , he chose to overcome it. Now he is a famous judge . Not only 44 he become successful, but he did so in a profession 45 he had to speak before others regularly. Had he not worked on his 46 ability, it would have been very limiting to his success in life and work.
Many people face far huger limitations, such as loss 47 legs or arms , being born extremely poor, 48 you do. But whatever the limitation, you’ll 49 find people who have overcome it. Helen Keller, who fell 50 and lost her sight and hearing at 19 months old, worked hard to be a famous woman with great 51 . Mark Inglis lost both his legs in a mountain climbing accident, 52 has since climbed Mt. Everest.
If one of them had told you what they hoped to achieve, you would have nodded kindly while 53 thinking to yourself that they had no chance . And yet the results speak for 54 .
Though most of us will never have to face such challenges , yet most of us will never achieve to the 55 that these people have either if we never seriously think of what we can do.

C．relationships

D．scholarships

B．Importantly

D．Fortunately

B．interviewed

A．communicating

A．congratulations

B．impressions

C．achievements

小题19:A. yourself B, ourselves C. themselves D. itself