4.When the t drops below zero.water will freeze. 查看更多

 

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A recent survey of 2000 parents in Britain showed that they are often afraid of science questions asked by their curious children only because they have no idea what the answer is. Here is a list of some simple questions that you can ask your parents to see if they know the answers.

    Q: Why is the sky blue?

    A: You probably know white sunlight is made up of seven colors. While it moves in a straight line when going through space, it starts to divide as it hits “raised area” in the atmosphere. The ones with longest wavelengths pass through easily. The blue , however , can be taken in by the gas molecules (分子) because it has a shorter wavelength , which in turn scatters (使分散) it in different directions. That’s why when you look up at the sky, it appears to be blue.

    Q:Why does the moon sometimes appear during the daytime?

    A: The simple answer to that is because just like any other object it is being lit by the sun. As long as it is around 45 degrees or even 90 degrees off the sun, it will receive light and be able to be seen. The only time it is not able to be seen during its 28-day orbit (轨道) around the earth is when it is right between the earth and the sun. That’s because its back , which is not lit by the sun, is facing us.

    Q: Where do birds/ honeybees go in winter?

    A: While the bird part is quite easy, since a lot of them get together and travel, the honeybee part is likely to puzzle your parents. It turns out that these busy insects stop being that active when the temperature drops below 50°F. Instead ,they get together in the lower central area of the hive (蜂巢)and form a ball around their queen. This helps keep both warm enough to survive the cold winter months.

1.The sky looks blue mainly because the color blue in the sunlight_______.

A. has the longest wavelength among all the colors

B. cannot be taken in by the gas molecules

C. doesn’t hit “raised area” in the atmosphere

D. cannot pass through space successfully

2.How long can’t the moon be seen during the daytime in a month?

A. 2                             B. 28                           C.30                                      D. 31

3.What do honeybees choose to do when the temperature drops below 50°F?

A. They choose to be active in the wild.

B. They choose to keep themselves warm.

C. They choose to travel to a warm place.

D. They choose to get together in the upper central area of the hive.

4.What is NOT explained in the passage?

A. Why is the sky blue?

B. Why is the moon able to be seen during the daytime?

C. Why do birds travel in winter?

D. Where do honeybees go in winter?

 

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根据句意和所给字母完成单词。
1. We use the e       to go up and down the building.
2. Look! It's raining outside. You'd better put on your raincoat or take an u       .
3. If you want to know the answer to the question, you should look t       books in the library.
4. Would you like to come and meet my parents and have a f       dinner with us?
5. When the t       light is red, you must stop and wait.
6. There is one child a       in the room. The other children are on the playground.
7. There are m       of reasons for me to stay here.
8. We were filled with g       when we heard of his death.
9. Yesterday Tom had a birthday party and I had many wines with a delicate f       .
10. The old men should be spoken to p       .

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根据句意及首字母补全单词。

1.Thanks for i_________ me to your party on Sunday.

2.I should work hard to make my country r_________ and stronger.

3.When the t_________ lights are red,you must stop and wait.

4.He's p_________ his vacation to Japan this summer.

5.Tom,to take n_________ in class is a good habit for you!

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根据句意及首字母填空。

1.Have you ever t_________ to the south of Italy?

2.There is a small i_________ in the center of the lake.

3.You must stop when the t___________ lights are red.

4.He speaks to his mother in a l_________ voice.

5.There are four s_________ in a year. I like autumn best. 

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根据句意及首字母提示,写出空白处所缺的单词。
1. When the t_______ lights are red, you must stop and wait.
2. Did you r_______ her letter the day before yesterday?
3. We must keep our classroom c_______ every day.
4. Look! It's raining outside. You'd better put on your raincoat or take an u_______.
5. N_______ Li Lei nor Liu Mei is in the classroom now.

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