Air is a colorless, tasteless and invisible（看不见的）gas that is around us. An “empty” drinking glass and an “empty” room, in fact, are not really empty. Each is filled with air. When the glass is filled with water, the water pushes the air out of the glass.
Air, as a gas, has no definite shape, but because it is matter, it takes up space and it has weight. It is easy to prove that air is something that takes up space. Stuff a piece of dry cloth（布）into the bottom of a glass so that it will not fall out when the glass is turned upside down. Push the upside down glass, holding straight up and down, into a jar of water till the glass is pletely covered. When the glass is taken out of the water, the cloth is still dry. The air inside the glass shows that it takes up space and keeps the water from ing in.
【小题1】Since air is matter, it has .A．room , and weight as wellB．both room and shapeC．either room or weightD．neither shape nor weight【小题2】The word “Stuff” means in Chinese. A．撕B．盖C．取掉D．塞【小题3】The writer tells that the experiment（实验） .A．is carried out in the spaceB．must be done in the labC．is made in the roomD．can only be done in the open airA
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(答案→)A
解析：这篇短文介绍了空气也要占据空间，并有一定的重量，并用一个实验说明了这个说法。
【小题1】根据Air, as a gas, has no definite shape, but because it is matter, it takes up space and it has weight.及上文描述可知空气也要占据空间，也有重量，故选A。
【小题2】联系下文so that it will not fall out when the glass is turned upside down.以便这个玻璃杯倒过来时，它不至于落下来。可知是塞住的意思。故选D。
【小题3】短文并没有直接指出这个实验是在哪里进行的，但是分析四个选项可知不是必须在太空，实验室进行，也不只是在户外才可以进行，故选C，在室内进行。为最佳答案。