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问题 填空题

Java语言的循环语句包括for语句、do-while语句和do-while语句，先循环后判断，循环至少被执行一次的是______。

答案

参考答案：do-while

解析： for循环必须事先知道循环要执行多少次，是确定的循环接口。 while循环称为“当型”循环，while循环先计算终止条件，条件满足时，才执行循环体内语句。 do-while循环称为“直到型”循环，do-while循环先执行循环体，然后计算终止条件。“直到型”循环结构的循环体至少被执行一次。

阅读理解

阅读短文，根据其内容回答问题。

      Americans love sports — they love to play them, to watch them on television, and to talk about them. But

this hobby sometimes has serious results — at least to the players. For example, when people play tennis,

sometimes they hurt their elbow (肘部) and in this way they develop "tennis elbow". Also it is easy to hurt a

knee in a football game. These injuries (损伤) happen while the player is having fun, but they still hurt.

      A few months ago, Kathleen Simmons, who loves playing volleyball, hurt her knee in a volleyball game. Her

doctor told her that she needed a very difficult operation (手术) or she might not be able to play again. She felt

very sad and didn't know what to do.

      Then Simmons learned about "video operation". With the help of this new science in medicine, doctors can

now repair many injuries and get people back on the playing field and back to their jobs much faster. Simmons

found a hospital that was using this new science and went to see the doctor there. The doctors told her the

operation could help.

      For this operation, her doctor didn't have to open her knee. Instead he put a very small camera lens (镜头)

inside her knee. The lens sent back pictures, which appeared on a television screen. As he worked, he could see

the inside of her knee on the TV. With the help of the large pictures on the screen, the doctor knew exactly what

to do when he was making the repairs.

      Simmons started walking five days after her operation. "My knee hurt a lot the first few days," she said. "But

I felt better very quickly." Now, six months after her operation, Simmons can do everything she did before her

injury. "It feels like a new knee," she said. "I can even play volleyball again."

1. Do Americans love sports? 

    _____________________________________________

2. What sport is Simmons interested in?

    _____________________________________________

3. What did the doctor put inside Simmons' knee?

    _____________________________________________

4. What problem may people have when they play sports?

    _____________________________________________

5. What's the advantage (优点) of the new science?

    _____________________________________________

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填空题

学校化学兴趣小组的同学设计了一套气体制取的实验装置，如图．若要进行（1）锌粒和稀硫酸反应制取氢气；（2）双氧水和二氧化锰反应制取氧气；（3）高锰酸钾分解

制取氧气；（4）大理石和稀盐酸反应制取二氧化碳，

请你思考一下，能用该套装置的是反应______（填编号）．装置中浓H2SO4的作用是______．写出反应（2）、（4）的化学方程式（2）______，（4）______．
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