题目内容
Every object has weight. But the center of its weight is not always in the middle of the object. If the top of an object is heavier than its bottom, it will fall over easily. We say that its center of gravity is high. But if the bottom is heavier, it won’t fall easily. Then we say that its center of gravity is low.
Look at the first picture. This empty box must fall over, because its center of gravity (C) is not above the line of its bottom (AB).
Now look at the second picture. There is some heavy iron in the bottom of this box. It will not fall, because its center of gravity is above its bottom.
【小题1】If the bottom of an object is ______ its top, it will fall over easily.
| A．lighter than | B．heavier than | C．no heavier than | D．as heavy as |
【小题3】The main idea of the passage is _________.
| A．why things fall over | B．a low center of gravity |
| C．a high center of gravity | D．that everything has weight |
【小题1】A
【小题2】C
【小题3】A
解析【小题1】根据文章内容If the top of an object is heavier than its bottom, it will fall over easily.可推测答案为A
【小题2】根据常识内容可知答案为C
【小题3】根据文章内容大意可知为A
阅读理解
Every object has weight. But the center of its weight is not always in the middle of the object, If the top of an object is heavier than its bottom, it will fall over easily. We say that its center of gravity
（引力）is high. But if the bottom is heavier, it won't fall easily. Then we say that its center of gravity is low.Look at the first picture, lifts empty box must fall over, bemuse its center of gravity (C) is not above the line of its bottom (AB).
Now look at the second picture. There is some heavy iron at the bottom of this box. It will not fall, because its center of gravity is above its bottom.
(1) Please point out which box will not fall?
(2) From the passage, we can infer that the Leaning Tower of Pisa does not fall is because_______.
[
]A
．the top of the tower is heavier than its bottomB
．the bottom of the tower is not heavier than its topC
．its center of the gravity is still above the line of its bottomD
．its center of the gravity is not above the line of its bottom(3) If an object has a low center of gravity, _______.
[
]|
A ．it won't fall |
B ．it won't fall easily |
|
C ．it is certain to fall over |
D ．its top must be heavier |
(4) Which of the following is TRUE according to the passage?
[
]A
．The center of the weight is always in the middle of the objectB
．The center of the weight is always on the objectC
．The center of gravity is not always in the middle of the objectD
．The center of the gravity is always high(5) The passage is mainly about _______.
[
]|
A ．why things fall over |
B ．a low center of gravity |
|
C ．a high center of gravity |
D ．that everything has weight |
| 阅读理解。 | ||||||||
| Collecting opens new worlds for you, but this is only one of the reasons to collect. Here are some more. Collecting tells stories. There is a story behind every object (物品) in a collection. There is your story: the story of when and where you get each object and what it means to you. The objects themselves also tell stories. If an object is old, it may tell the stories of other people who once owned (拥有) or used it. If it's new, it can tell you a lot about its own time and place. Collecting teaches you many things. Historical (历史的) objects teach us about important events, great heroes, or everyday life in the past. New objects show today's technology (技术) and our way of life. Plants, animals and stones teach us about nature. Collecting lets you share your knowledge with others. When you show your collection to your family or friends, you teach them new and interesting things. Kids all over the world are collectors, so while you're having fun learning about your collection, you can also make new friends and share your knowledge. | ||||||||
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