题目内容

Plants depend on nitrogen ________.


  1. A.
    staying alive
  2. B.
    staying living
  3. C.
    to stay alive
  4. D.
    to stay living
C
解析：stay alive指保持活着这一状态。alive足形容词。
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阅读理解

　　There are many kinds of animals that live in the forest, such as mice, rabbits, squirrels, owls (猫头鹰) and hawks. Animals in the forest depend on one another for food.

　　Many small forest animals, such as mice, eat green plants for food, and then they, themselves, are eaten by larger animals. This is called a food chain.

　　A food chain begins with the sun. The green plants in the forest use the sun's energy (能源) to make food for themselves. This process, or action, is called photosynthesis (光合作用).

　　Forest plants produce flowers and seeds that are eaten by mice and other animals. The mice get their energy from the plants, and the mice become food for a larger animal, such as the hunting hawk. So, the energy from the sun passes from the plants to the mice to the hawk. A break in any link of this food chain means that some animals may not have enough food to live.

1．Photosynthesis takes place when________.

[　　]

A．larger animals eat small animals

B．green plants use the sun's energy to make food

C．forest animals eat the food made by green plants

D．the food chain is broken

2．What is the first link in a food chain？

[　　]

A．The sun.
B．The earth.
C．Green plants.
D．Forest animals.

3．Animals sometimes cannot find enough food because________.

[　　]

A．it's cloudy

B．there is very little food in a forest

C．photosynthesis stops

D．there is a break in the food chain

4．What does the food chain show about living things？

[　　]

A．They depend upon each other.

B．Small animals eat as much as large animals.

C．Plants with flowers are the most important.

D．Plants are more than animals.

5．Which of the living things below fills the missing link in this food chain？

[　　]

A．rabbits
B．mice
C．green plants
D．owls
阅读短文，根据其内容回答问题。
        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 have no teeth and claws. But plants can defend (保护)
themselves by using both physical and chemical ways.
        Some plants have their own ways to keep animals away. For example, the leaves of the holly (冬青) plant
have sharp prickles (刺) that stop grass-eating animals. Holly leaves on lower places have more prickles than
leaves on upper places. This is because the lower leaves are easier for most animals to reach.
        Some plants, such as the oak tree (橡树), 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 worm (虫子) bites a tobacco leaf (烟叶), the leaf produces a chemical smell.
        Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has
prickly leaves, and each prickle has poisonous water (毒液). Only one experience with this kind of plant will
teach an animals to stay away from it is the future.
1. Can plants move from place to place?
    ____________________________________________________________
2. Can plants defend themselves by physical ways or by chemical ways?
    ____________________________________________________________
3. Why lower holly leaves have more prickles than upper ones?
    ____________________________________________________________
4. How does tobacco defend itself against an attack from a worm?
    ____________________________________________________________
5. What kind of experience will teach an animal to stay away from a plant in the future?
    ____________________________________________________________
阅读理解。
     A prairie is a type of grassland. Prairies are made up of a complete interdependent ecosystem. This means
that all kinds of plants and animals in a prairie region depend on one another for survival (生存). The members
of a prairie ecosystem include grasses, flowering plants, animals, soil (土壤), sand, and fire.
     You may look at a prairie and think there's nothing there but grass, but that' s not true. Most of the prairie's
living things are below the ground. Underneath the prairie' s surface are roots and bulbs (根茎). The roots of
the prairie flowers and grasses run deep. Some of them are as deep as 3.5 metres below the ground.
     It is impmtant for the roots to run deep because fires are a part of the prairie ecosystem. When a fire bums
through the prairie, plants with shallow (not deep) roots can not survive. Plants that have deep root systems
are able to survive the fires. When fire burns across a prairre, it bums dead plants from the top and returns
those nutrients (养料) to the soil. This adds to the richness of the prairie soil. Prairies have some of the
richest soil in the United States. This cycle of growth and buming has been going on for thousands of years.
Big bluestem is the plant that gives parts of the prairie the name "tallgrass prairie".
     Big bluestem has very deep roots, and its stems (茎) are often 2 metres tall.
     The American bison (野牛) or buffalo, is the country' s largest land animal. Its home is on the prairies. In
1830, there were an estimated 30 million to 60 million bison in the United States. By 1889, Americans had
made the bison population to fewer than l,000 animals. Through great efforts, bison are being reintroduced to
the prairies. They are also kept in zoos. The bison population has grown to several hundred thousand today.
     Humans have put the prairie ecosystem in danger. Through constant farming, building, fire prevention,
and ignorance( not knowing) of how the prairie works, the United States has lost much of its natural prairie.
Through education and other work , we can hope to save some of it.
1. A prairie is a type of  ________.
A. plants
B. animals
C. grassland
D. soil
2. What is the meaning of "interdependent ecosystem" in the first line?
A. All things in a prairie region depend on one another.
B. Animals live on plants in a prairie region.
C. Fire plays an important role in a prairie region.
D. Soil has a close relationship with a prairie region.
3. By 1889, the bison population was ________.
A. about 30 million
B. fewer than a thousand
C. about 60 million
D. several hundred thousand
4. We can leam from the article that ________.
A. fires may destroy a prairie and therefore must be prevented
B. the interdependent ecosystem is both below and above ground
C. the prairie ecosystem is in danger because of farming and building
D. people haven't realized that they are losing their natural prairie
阅读理解。
    Plants are very important living things. Life can't go on living without plants.This is because plants can
make food from air, water and sunlight. Animals get their food from plants, animals and so on, so animals
and man need plants in order to live. This is why we find that there are so many plants around us.
1. The passage doesn't tell us ______.
[     ]
A. why there are so many plants around us
B. we can't live without plants
C. how important plants are for man and animals
D. how many kinds of plants there are in the world
2. From the passage, we know that animals and man depend on plants; while plants depend on ______.
[     ]
A. air, water and sunlight
B. animals and man
C. animals only
D. man
3. What will happen (发生) to man if there are no plants in the world?
[     ]
A.They can go on living.
B.They can't live.
C. They can eat animals.
D. We don't know.
4. Man gets ______ from plants and animals.
[     ]
A. air
B. water
C. sunlight
D. food
5. Which of the following is right?
[     ]
A. Man will not be hungry without plants or animals.
B. Plants are food for animals.
C. Animals make food from air, water and sunlight.
D. Plants are not as important for us as air, water and sunlight.

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