“Leaves are to plants lungs are to human beings, the biology teacher said to the students. A．that B．which C．what D．whose 题目和参考答案——青夏教育精英家教网—

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“Leaves are to plants ___ lungs are to human beings,” the biology teacher said to the students.

A．that B．which C．what D．whose

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Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back. Plants certainly cannot run away, and they lack teeth and claws. But plants can defend themselves by using both physical and chemical means.

Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines (刺) that discourage grass-eating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach.

Some plants, such as the oak tree, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal's teeth.

Many plants also have chemical defenses. Some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar (毛虫) bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.

Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has prickly (多刺的) leaves, and each prickle contains poisonous venom (毒液) A single experience with this kind of plant will teach an animal to stay away from it in the future.

68. The holly plant has more spines on the lower leaves because most animals________.

A. are not tall enough B. like the lower leaves only

C. are not clever enough D. can get the lower leaves easily

69. To defend themselves, oak trees use________.

A. chemical means B. physical means

C. bitter chemicals D. sandy materials

70. How does tobacco protect itself against an attack from a caterpillar?

A. Its leaves fight against the attack by physical means.

B. Its roots send a messenger to discourage the caterpillar.

C. Its roots increase the production of nicotine when it is attacked.

D. Its leaves produce poisonous sand to drive the caterpillar away.

71. What would be the best title for this passage?

A. Plants and Animals B. How Plants Defend Themselves

C. Attacks and Defenses D. How Animals Eat Plant Leaves

Koalas are pictured everywhere in Australia-on cleaning products, on “boxes of chocolate, on sports team shirts. Yet the animals live only in pockets along the east coast.
They once inhabited the entire coastline. The koala population dropped after farmers cut down many of the forests where koalas lived, and hunters killed the animals for their fur.
By the early 1900s, “koalas were basically shot out of south Australia,” says ecologist Bill Ellis, who studies the relationships among living things and their environments.
I recently joined Ellis and his team in a forest on St Bees Is land, 19 miles off the northeastern coast of Australia, with eight other volunteers. The island is a natural laboratory, yielding findings that may help protect koalas elsewhere on the continent.
The volunteers searched the island for koalas in the blue gum trees. When we found a koala, we gathered information about the trees in the area.
Blue gum is a species of the eucalyptus tree in which the funny leaf eaters spend most of their time. Eucalyptus trees are native to Australia, and their leaves are the main food source for koalas. Although koalas can walk on the ground, they are better suited for life in the canopy, the high cover of branches and leaves in a forest.
What has Ellis’s research told him so far? The population of St Bees seems to be healthy. Yet Ellis wonders whether the koalas might be heading for hard times. The island is overrun with wild goats, and Ellis thinks the goats are eating the small blue gum trees.
Without those trees, the koalas will run out of food in the future. Ellis hopes more research will help him understand how to protect the blue gum trees-and the koalas that depend on them. “I think that’s what everyone is trying to do-to make a difference.” Ellis says.
59. It can be inferred from the first paragraph that     .
A. koalas’ pictures can be found everywhere in the world
B. koalas in Australia like to eat chocolate
C. only in the east coast of Australia can you find koalas
D. you can buy the pictures of koalas only in the east coast of Australia
60. Which of the following is TRUE about koalas?
A. They usually hide in a cave.     B. They feed on the leaves of blue gum trees.
C. They prefer to walk on the ground. D. They don’t adapt to the high cover of branches.
61. What will Ellis most probably start to do next?
A. To keep the population of St Bees healthy.
B. To kill all the goats on the island.
C. To find some new foods for goats.
D. To protect blue gum trees for koalas.
62. The purpose of writing this passage is to      .
A. expect people to concern about the life of koalas
B. record trip to Australia for watching koalas
C. present some basic knowledge of koalas’ life
D. introduce the ecosystem of wildlife in Australia

It’s a sure sign that summer is over and winter is on the way — leaves that were once deep green turn red, yellow and bright orange. It happens every autumn. But did you ever wonder why?

The leaves start changing color when the nights start getting longer and the temperature starts getting cooler. Some scientists think that as the number of daylight hours shrinks, the leaves stop making chlorophyll which makes plants green. The reason is that the process of making chlorophyll requires sunlight. But according to horticulture (园艺) educator Susan Rose from Colorado State University, it turns out leaves don’t really change color at all. “The fall colors are actually there all along,” she said. “But they are covered by the green chlorophyll. As the chlorophyll stops being produced, the other colors can shine through.”

The kind of color that the leaves are going to change to is determined by the plant’s genetic (基因的) background. In some places, the leaves start changing color in September — before autumn even officially begins. In other places, they don’t change until late October or even November. Some scientists say the leaves have been changing color later than usual in recent years. And they think global warming has something to do with that.

In one study, researchers found that the growing season in the Northern Hemisphere was nearly a week longer, on average, in 2008 than it was in 1982. And a professor from Harvard University found that the leaves, west of Boston, Massachusetts, are changing color about three days later than they used to. However, other scientists disagree with the global warming theory. Susan Rose said the leaves in her part of Colorado are changing “right on schedule.” But the leaves in other parts of that state are running a little late. “The lateness in the mountains may have something to do with the really warm late summer and early fall,” she said. “But I’m afraid that’s just a guess.”

1.According to Susan Rose, _____.

A．the fall colors are always in leaves

B．leaves make chlorophyll all the seasons

C．leaves’ changing color have nothing to with the weather

D．leaves begin changing color because they start making chlorophyll

2.The underlined word “shrinks” in Paragraph 2 could best be replaced by _____.

A．reduces B．increases C．lasts D．appears

3.Scientists guess leaves change color later than usual probably as a result of _____.

A．genetic background B．dry weather

C．global warming D．low temperature

4.The purpose of the last paragraph is to tell readers _____.

A．why leaves change color at fall

B．leaves change color at different time

C．the effects of the global warming on plants

D．different opinions on the lateness of leaves’ changing color

The koala(考拉) is possibly one of the best known Australian animals, and is found in four states: Queensland, New South Wales, Victoria and South Australia. The word “koala” comes from an Australian aboriginal word meaning “no drink”.

Sometimes people call them “koala bears” but koala is not a bear. It belongs to a special group of Australian mammals, called marsupial(有袋类). Female marsupials have a pouch where the baby animals live after they are born.

Koalas have soft, thick, grey or brown fur on their backs. The fur on the stomach is white. Koala that live in the south have thicker fur than those in the north because of the cold winters, whereas the koalas in the northern part of the country live in warm to hot weather most of the year so have thinner fur. A koala has a large hairless nose and round ears. Koalas don’t have tails. Adult koalas measure between 7 and 14 kilograms.

Koalas spend nearly all their time in the trees using their sharp, curved claws and long toes to climb about and to hold on to the tree branches. They sleep most of the day, and feed and move from tree to tree mainly at night.

The reason koala sleep for much of the day is because their food eucalyptus(桉树) leaves are very tough so they use a lot of energy to digest. Sleeping saves energy. Eucalyptus leaves are poisonous to almost every other animal. Koalas rarely drink water; they get water from the leaves they eat.

Each koala has a home range made up of several trees that they visit regularly. They normally do not visit another koala’s home trees except that a male is looking for a female to mate with.

1.Which of the following statements is NOT true about the name “koala bear”?

A．The name was given by the native in Australia

B．The word “koala” is an original English word

C．The name describes one of its living habits

D．The name is partly false

2.Which of the following is closest in meaning to the underlined word “punch”？

A．House B．Cave C．Pocket D．Nest

3.Why do the koalas live in the south have thicker fur than those in the north?

A．The thicker fur can protect them from the colder weather

B．It’s always hot in summer in the north

C．It’s always cold in the winter in the south

D．They have to move to the north in the winter

4.Why do koalas sleep much in the day?

A．Their foods are poisonous

B．They want to save energy for the activities at night

C．They can’t get enough energy from their tough foods

D．They can’t get enough water from their leaves

When nature is left alone, a balance is reached among the animals and plants living in one area. But when man starts his work in nature, the balance is likely to be destroyed. He grows a crop and takes it away to eat ;then there are no dead leaves to fall on the ground, holding water while it sinks into the surface, or decaying (腐烂) and adding humus (腐殖质) to the soil. Unless a farmer acts with knowledge and skill, he is therefore most likely to make the land poorer. To take the place of the useful matter in the crops that he removes, he uses some kind of fertilizer (肥料). Chemical fertilizers are of great help, but the waste products of animals and decaying remains of plants should also be put on the land. In some places, it is a habit to burn waste material lying about, but such burning destroys the useful matter in the dead plants. Although the ashes that are left are valuable when put on the land, a better practice is to bury the waste so that it decays and increases the humus in the soil.

In the past, when the world population was much lower than it is now, a man had little difficulty in ordinary times in growing the food that was needed. When a field had been used some years and had become tired, the farmer could move to another place. The tired land then slowly recovered. By and by grasses and other plants would appear on it and its productive power would slowly return to normal through their decay. But nature, left alone, would take a long time to bring back the land to its former state; the length of time required would depend on local conditions, but it might well be ten years.

It is a bad practice to grow the same crop in a field year after year. If the crop is changed, the land will suffer less because it is treated and used in a different way. Different plants have different effects on the soil. Therefore, a change of crop will do less harm than the growing of the same crop year after year and a regular change to grass will do good to the soil. Much will therefore be gained if different crops are grown one after another, a method known as the rotation (轮作) of crops.

1.According to the passage, the land will become poorer ( )

A. if all the dead leaves are cleared away B. if the humus is increased after the harvest

C. if dead leaves decay in the soil by themselves D. if waste plant material lying about is buried

2.We can learn from the passage that the tired land has slowly recovered ( )

A. when grasses and other plants appear again

B. when the treatment is given by nature alone

C. after new grasses and other plants have decayed again

D. after nature has been left alone for several months

3.A modern farmer can hardly move to another place as he did before because ( )

A. the productive power of a new field isn't higher than that of an old one

B. there are few free fields left for him to do farming

C. it takes a farmer more than ten years to start farming in a new field

D. there will be too many grasses in a new field to grow crops

4.It is most likely that the author will go on to ( ) in the paragraph following the passage above.

A. introduce other methods of planting crops B. deal with how to prevent land getting tired

C. start another topic of how to make use of land D. further explain what the rotation of crops is

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