问题 选择题

下列分类或归类正确的是(      )

①液氯、氨水、干冰、碘化银均为纯净物    ②CaCl2、NaOH、HCl、IBr均为化合物

③明矾、水银、烧碱、硫酸均为强电解质    ④C60、C70、金刚石、石墨均为碳的同素异形体

⑤碘酒、淀粉、水雾、纳米材料均为胶体

A.①③④

B.②③    

C.②④    

D.②③④⑤

答案

答案:C

题目分析:①氨水是混合物。错误。②CaCl2、NaOH、HCl、IBr均为化合物。正确。③水银是单质,不是电解质。错误。④C60、C70、金刚石、石墨均为由同种元素组成的不同性质的单质。是碳的同素异形体。正确。⑤碘酒是溶液,不是胶体。错误。所以正确的选项为B。

阅读理解

阅读理解。

  What is blood? Blood is a thick, red fluid which carries oxygen, water and

food to all parts of the body. It keeps the body at the right temperature (温度) and

protects it from disease.

  If you lose a lot of blood, you need new blood. You can receive new blood

from other people. This is called a blood transfusion (输送).

  People can donate (捐献) blood at a Red Cross Blood Bank. People who

give blood are called blood donors (捐献者). Some people sell their blood but

many others donate it.

  Donating blood doesn’t hurt you and it doesn’t take long. First a nurse take a

drop of blood from your finger and tests it. She does this to make sure that your

blood is healthy. Then you lie down on a bed and another nurse checks your

blood pressure (血压). After that the nurse puts a needle into a vein in your arm.

The needle is attached to a tube. The blood flows through the tube into a plastic

bag. After about 10 minutes, when the bag is full, the nurse takes the needle out of

your arm. You stay on the bed and rest for a few minutes. Finally you go into

another room and have something to eat.

  For a healthy person, donating blood is not harmful or painful. But the

blood he or she donates may save someone's life.

1. Where can people go to donate blood?

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2. Why does the nurse first take a drop of blood from the finger?

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3. What do you do after the nurse takes the needle out of your arm?

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4. Do you think you need something to drink after donating blood?

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5. Is donating blood harmful for healthy people according to the passage?

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多项选择题