题目列表(包括答案和解析)
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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 |
A.why things fall over | B.a low center of gravity |
C.a high center of gravity | D.that everything has weight |
任务型阅读
Safety Activities for Middle School KidsSchool is not the safe place as it used to be.How do we keep school safer? How do we help students stay away from danger? There are many activities that teachers can do to teach safety in an easy way.Here are some stories from the students who have had the safety class in No.1 Middle School.
Mike Smith:About Sports Safety
Once, our head teacher made up a story about sports safety.All we needed to do was to point out safe and unsafe sports behaviors in the story.From this lesson, we knew we should always do warm-up activities before playing sports and drink some water after that.
Amy Young:About Classroom Safety
Yes, making up stories is a good way to learn and enjoy ourselves.We were once asked to make up a story about a boy called Little Naughty(调皮的).He always did something naughty in the classroom and got himself into trouble.In this way, we learned to behave(为人处世)well and get on well with each other.
Frank Green:About Fire Safety
In our school, we have a fire emergency response practice(火警应急演习)in September every year.So we know where to go if there is a fire in a school.We learn to use the fire extinguisher(灭火器), too.But I don't think we should be allowed to put out the fire by ourselves, it's too dangerous for young students like us.
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.
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
2.Please point out which box will not fall.
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
短文填空,选择适当的单词填空,每词限用一次。(有两个多余的选项)
write, influenced, events, least, travel, personal, Internet, improve, useful, most |
Over then years ago, blogs(博客) were mostly just online diaries written by teenagers. Today, they are so much more. Blogs have become powerful enough to influence the media(媒体), or even the governments.
It's said that the number of blogs on the 8. is between 10 to 32 million. Many of these are 9. Blogs that people use to keep in touch with their friends. But some are public ones on superstars, sports and up-to-date 10. .
Studies show that 30 percent of Americans have read a blog at 11. once. Even is people do not read blogs regularly(定期地), they might still be 12. By them in some way.
Now people are starting to ask: Will blogging take the place of other types of media? The answer is "NO". Most bloggers do not do first-hand reporting. Unlike reporters, they do not
13. to the places or meet people they 14. about. They just get information from other media for their blogs. But blogs might help 15. The quality of other media. Reporters are more careful when they know bloggers will point out their mistakes.
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