不定项选择关于材料的电阻率,下列说法正确的是( ) A.把一根长导线截成等长的三段

题型:不定项选择

问题:

不定项选择
关于材料的电阻率,下列说法正确的是(   )
A.把一根长导线截成等长的三段,则每段的电阻率都是原来的1/3

B.材料的电阻率随温度的升高而增大

C.纯金属的电阻率较合金的电阻率小

D.电阻率是反映材料导电性能好坏的物理量,电阻率越大的导体对电流的阻碍作用越大

考点:电阻定律、电阻率
题型:不定项选择

根据短文内容,选择最佳选项.

    I suppose when you grow up in one place, you have friends whom you've known since childhood.

But as a child who moved a lot, my oldest friendships are with my cousins.

    On our return from Guam, my parents, sisters and I walked off the plane in Alexandria. All my cousins

were there to meet us.

    I was excited to see them again. The last time I'd seen Don, Sherri and David was two years before.

That summer we'd caught fireflies(萤火虫) and watched Don and his friends play a game. Some boys

acted like a bull(公牛) with a rope(绳子). His friend held the rope and Don rode on it. When Don fell

off, he got up and tried again.

    Just like riding that bull, Don put his heart into everything he did. As a young man he was told he got

cancer(癌症). But he fought it and never gave up. Like what he did that summer, he held tight(紧紧地),

falling off a few times and trying again. I was excited and proud of my cousin for planning and going after

his dream. I wished his ride would have lasted longer.

1. The writer and his family returned to Alexandria      .

A. by boat              

B. by ship

C. by air                

D. by train

2. The writer and his cousins       in the summer two years ago.

A. became good friends

B. moved to Guam

C. rode a bull

D. caught fireflies

3. What does the underlined word "held" mean in the passage?

A. 抓住    

B. 容纳    

C. 扣留    

D. 举办

4. When did Don know he got cancer?

A. When he was born.

B. When he was a young man.

C. Two years ago.

D. Last summer.

5. From the last paragraph, we know Don is a man who        .

A. is very shy            

B. never gives up

C. has a bull              

D. is very foolish

题型:不定项选择

严格控制轨道不平顺中严格控制()是基础。

题型:不定项选择

4がつなのに あついですね。なつの (    )ですね。

A.らしさ

B.つもり

C.こと

D.よう

题型:不定项选择

施工前的机具准备包括哪些内容?

题型:不定项选择

摆动导杆机构有无急回特性?

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