Plants don’t have legs to run or arms to throw a ball, but that doesn’t 21 that plants can’t 22at all． If you watch closely, you will see 23 plants bend their stems and flowers toward the sunlight 题目和参考答案——青夏教育精英家教网—

题目内容

Plants don’t have legs to run or arms to throw a ball, but that doesn’t 21 that plants can’t 22at all． If you watch closely, you will see 23 plants bend their stems and flowers toward the sunlight every day． 24 are plants able to move 25 they don’t have bodies like animals do?

Plants cells 26 chemicals called auxins（植物生长素） to 27 them to move． To find out how chemicals 28, think of a plant outside in a garden． Because the sun rise in the east in the morning, the 29 side of the plant stem is in the light． But the west side of the stem is in the _30 ． So the cells in the shaded side of the stem 31 to make auxins, which make that side of the stem grow 32 while the side of the stem 33 the sun grows much slower． When the shaded side grows faster, it makes the whole stem 34 toward the sunlight, and 35 leaves and flowers on the stem face the 36 too． When the sun moves to the west in the afternoon, the 37 thing happens and the stem bends toward the light again．

38 is a reason why the plant produces chemicals that make stems 39 the sun． Leaves 40 sunlight to make food for the plant． So it is important for stem to get as much light as they can．

21．A． tell B． promise C． show D． mean

22．A． grow B． go C． move D． stand

23．A． most B． few C． tall D． short

24．A． why B． How C． Where D． When

25．A． because B． although C． if D． as soon as

26．A． make B． accept C． keep D． send

27．A． push B． bring C． help D． stop

28．A． form B． work C． flow D． look at

29．A． west B． bright C． opposite D east

30．A． shade B． light C． dark D． garden

31．A． stop B． begin C． continue D． help

32．A． fast B． slowly C． up D． badly

33．A． near B． toward C． against D． in

34．A． bend B． fall C． turn D． walk

35．A． some B． all C． few D． no

36．A． stem B． west C． ground D． sun

37．A． common B． strange C． same D． different

38．A． This B． That C． It D． There

39．A． follow B． circle C． catch D． pull

40．A． receive B． have C． use D． reduce

DCABB

ACBDA BABAB DCDAC

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A strong wind can be a dangerous thing — sometimes it is powerful enough to knock you off your feet. But to plants, the wind is a source of new life, carrying them or their spores (孢子) thousands of miles.

A NASA satellite called QuikSCAT has discovered highways of wind over the Earth's oceans. Scientists believe these invisible roads may explain why many nonflowering plants, such as mosses (苔) and lichens (地衣), grow where they do.

The satellite is able to send microwaves (微波) from space to the surface of the ocean. The pattern of signals that come back shows which way the winds are blowing.

Using this data, the scientists studied a group of islands in the southern hemisphere (半球), near Antarctica．Winds tend to blow anticlockwise (逆时针) in this region, but there are lots of local differences.

When the researchers compared these local patterns to botanical (植物学) data, they found that the wind had an important effect on where species of mosses, lichens, and other nonflowering plants grow.

For example, Bouvet Island and Heard Island, share 30 per cent of their moss species, 29 per cent of liverworts (叶苔), and 32 per cent of lichens — even though they are 4,430 kilometers apart. In contrast, Gough Island and Bouvet Island, separated by just 1,860 kilometers of sea, share only 16 per cent of mosses and 17 per cent of liverworts. They have no lichens in common.

Ferns (蕨类植物) and flowering plants don't travel as well in the wind, so they don't show the same kinds of distribution (分布) patterns.

This story is about _____.

A．the discovery of wind highways B．how wind travels

C．how wind affects different plants D． one function of the wind

The underlined word "data" in the fourth paragraph means _____.

A．signal B．pattern C．information D． research

Which of the following is wrong?

A．Bouvet Island, Heard Island and Gough Island are all in the southern hemisphere.

B．Winds in the researched area blow anti-clockwise.

C．The scientists shouldn't base this research on how winds affect where ferns grow.

D． Without the discovery of QuikSCAT, the research wouldn't have made sense.

Which of the following diagrams shows the correct position of the islands?

Scientists are trying to make the deserts into good land again．They want to bring water to the deserts，so people can live and grow food．They are learning a lot about the deserts．But more and more of the earth is becoming desert all the time．Scientists may not be able to change the desert in time．
Why is more and more land becoming desert？Scientists think that people make deserts．People are doing bad things to the earth．
Some places on the earth don’t get much rain． But they still don’t become deserts． This is because some green plants are growing there． Small green plants and grass are very important to dry places． Plants don’t let the sun make the earth even drier． Plants do not let the wind blow the dirt away． When a bit of rain falls， the plants hold the water． Without plants， the land can become desert more easily．
【小题1】Deserts ＿＿＿＿＿＿＿＿．

A．never have any plants or animals in them

B．can all be turned into good land before long

C．are becoming smaller and smaller

D．get very little rain

【小题2】Small green plants are very important to dry places because ＿＿＿＿＿．

A．they don’t let the sun make the earth even drier

B．they don’t let the wind blow the soil away

C．they hold water

D．All of the above．

【小题3】Land is becoming desert little by little because ＿＿＿＿＿＿．

A．plants can’t grow there

B．there is not enough rain

C．people haven’t done what scientists wish them to do

D．scientists know little about the deserts

【小题4】Why is more and more land becoming desert according to this passage？

A．Earthquakes make deserts.	B．Wind makes deserts.
C． Lack of water makes deserts.	D．People make deserts．

An allergy (过敏反应) is a strong reaction to a substance. Many things can cause allergies. The most common cause is pollen (花粉), which is usually produced by trees in the spring, grasses in the summer and weeds in the fall, as part of their reproductive process.
Other causes include organisms, chemicals, plants and dead skin particles (微粒) from dogs and cats can also cause allergic reactions. So can insect stings and some food.
The most common kind of allergic reactions is itchy (痒的), watery eyes and a blocked or watery nose. Allergies can also cause red, itchy skin. Some reactions can be life-threatening, for example, when breathing passages become blocked.
It is not always easy to avoid allergies. Drugs may offer an effective treatment. Another treatment used in some cases is called immunotherapy (免疫疗法). A patient is injected with small amounts of the allergy-causing substance. The idea is that larger and larger amounts are given over time until the patient develops a resistance in his body.
In the United States, experts estimate that up to 8% of young children have food allergies. Every year these allergies cause about 30,000 cases with severe reactions that require immediate treatment. It can result in breathing trouble and in some cases death. It is said that about 100 to 200 people will die. It says most of the reactions are caused by peanuts and tree nuts like walnuts.
People can also be allergic to medicines. The American Academy of Allergy, Asthma and Immunology says about 10% of bad reactions to commonly used medicines are allergic. In other words, a person’s immune system overreacts and produces an allergic reaction. The most common reactions include skin rashes (皮疹), itching, breathing problems and swelling in areas such as the face.
【小题1】 Allergies seldom occur in winter because ______.

A．plants don’t flower in cold weather	B．people usually wear thick clothes
C．pollen is active below freezing point	D．the weather is not too cold for viruses

【小题2】What will happen if one’s breathing passages get blocked?

A．It is nothing serious.	B．One’s life is at risk.
C．One has to be sent to hospital.	D．One is sure to breathe easily.

【小题3】 According to immunotherapy, the patient is supposed to ______.

A．take some medicines to produce antibodies

B．have immediate operations

C．be given the allergy-causing substance until he develops a resistance

D．be exposed to enough allergy-causing substances

【小题4】The best title would be “________”.

A．The ABCs of Allergies	B．The Cause of Allergies
C．The Treatment of Allergies	D．The Prevention of Allergies

Scientists are trying to make the deserts into good land again. They want to bring water to the deserts， so people can live and grow food. They are learning a lot about the deserts. But more and more of the earth is becoming desert all the time. Scientists may not be able to change the desert in time.

Why is more and more land becoming desert？Scientists think that people make deserts. People are doing bad things to the earth.

Some places on the earth don’t get much rain. But they still don’t become deserts. This is because some green plants are growing there. Small green plants and grass are very important to dry places. Plants don’t let the sun make the earth even drier. Plants do not let the wind blow the dirt away. When a bit of rain falls，the plants hold the water. Without plants，the land can become desert more easily.

1.Deserts ＿＿＿＿＿＿＿＿ .

A．never have any plants or animals in them

B．can all be turned into good land before long

C．are becoming smaller and smaller

D．get very little rain

2.Small green plants are very important to dry places because ＿＿＿＿＿＿.

A．they don’t let the sun make the earth even drier

B．they don’t let the wind blow the soil away

C．they hold water

D．All of the above.

3.Land is becoming desert little by little because ＿＿＿＿＿＿.

A．plants can’t grow there

B．there is not enough rain

C．people haven’t done what scientists wish them to do

D．scientists know little about the deserts

4.After reading this passage， we learn that ＿＿＿＿＿＿＿＿.

A．plants can keep dry land from becoming desert

B．it is good to get rid of the grass in the deserts

C．all places without much rain will become deserts

D．it is better to grow crops on dry land than to cut them

Why is more and more land becoming desert？ Scientists think that people make deserts. People are doing bad things to the earth.

Some places on the earth don’t get much rain. But they still don’t become deserts. This is because some green plants are growing there. Small green plants and grass are very important to dry places. Plants don’t let the sun make the earth even drier. Plants do not let the wind blow(吹) the dirt away. When a bit of rain falls， the plants hold the water. Without plants， the land can become desert more easily.

1. Deserts ________.

A. never have any plants or animals in them

B. can all be turned into good land before long

C. are becoming smaller and smaller

D. get very little rain

2. Small green plants are very important to dry places because __________.

A. they don’t let the sun make the earth even drier

B. they don’t let the wind blow the soil away

C. they hold water

D. All of the above.

3. After reading this passage, we learn that __________.

A. plants can keep dry land from becoming desert

B. it is good to get rid of the grass in the deserts

C. all places without much rain will become deserts

D. it is better to grow crops on dry land than to cut them

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