题型:阅读选择 题类:常考题 难易度:普通
黑龙江省哈尔滨四十七中2016-2017学年八年级上学期英语开学验收试卷
Why don't birds get lost on their long flights (飞行) from one place to another? Scientists have studied this puzzle for a long time. Now they're starting to fill in the blanks(空白).
Not long ago, experiments showed that birds use the sun to guide them during daylight hours. How do birds fly at night? Tests with artificial stars, which are made by people, have proved that certain night-flying birds are able to follow the stars in their long-distance flights.
They found a bird that spent its lifetime in a cage and never flew under a natural sky. But it was born with the ability to use the stars to look for the direction. This bird's cage was placed under the sky filled with artificial stars. Any change in the position of the artificial stars caused a change in the direction of the bird's flight. From the experiment, they found that the bird tried to fly in the same direction as those artificial stars moving under the natural sky.
But the stars are of course birds' main ways of navigation (航行), when the stars are hidden by clouds, they can still find their way by such landmarks (路标) as river courses, mountain ranges (山脉), coast lines and so on. Because of this ability, people use the dove (鸽子) to send messages in some fields. For example, the doves were used to send messages in both World War I and World War II. During that time, thousands of doves were used to carry important messages in order to save the lives of many thousands of people. So it is also the symbol of peace.
But when it's too dark to see these things, the doves are not able to find their way. They only circle helplessly and get lost.
根据短文内容选择最佳答案.
If you are riding a bike in foreign countries, you need to know what these traffic signs mean.
1 | This sign means “walk”, you can cross the street along with other people. | |
2 | This sign is the “don't walk” sign. It means you should stop to wait for a while until the sign of “walk” is showing. | |
3 | This sign means that there is a bike lane. If you see such a sign, you must use the bike lane. | |
4 | Car drivers and bike riders must come to a complete stop at “STOP” signs. | |
5 | This sign means you are coming to a zebra crossing. You must slow down to allow people in the zebra crossing to cross the street. | |
6 | This sign means parts of the road are rough. Be careful! Rough roads make you fall off your bike. |
A
▲How nosebleeds happen: |
Nosebleeds are very common among children and often result from activities such as blowing the nose too hard or getting hit on the nose during play.Catching colds or the flu can also cause (引起) nosebleeds.Usually,bleeding isn't very serious and it will stop in less than ten minutes. |
▲When nosebleeds happen: |
Your child may be frightened that there is something seriously wrong.Crying may make the bleeding worse, so it is important for you to tell him that he will be fine. |
▲How to give first aid: |
Let your child sit upright(直立) and tell him to put his head down. |
Help your child press the sides of the nose for ten minutes.Do not stop to see if the bleeding has stopped. |
▲If first aid works: |
Rest your child for the next 12—24 hours.Tell him to do quiet activities such as drawing,reading a book or watching TV. |
Tell him not to take a hot shower for at least 24 hours after a nosebleed. |
Tell him not to touch or blow his nose for 24 hours. |
▲If first aid doesn't work: |
You'd better take him to hospital. |
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