All living things need energy to live and grow. This energy comes first from the sun. Plants use water and sunlight to make their own food. Animals can not make their own food, and they eat plants. Other animals then eat the plant eaters.
A food chain shows what eats what. It might show that zebras eat grass and then lions eat zebras.
Lions also eat other animals. Zebras eat other kinds of plants. So it takes more than one food chain to show how lions and zebras get their energy.
A food web shows how food chains work together. From it we can see how energy moves from plants to animals.
Plants and animals that live in hot, dry deserts depend on water as well as food. Creosote bushes have small leaves that hold water. Their seeds provide food and water for kangaroo rats. Kangaroo rats don’t need to drink water. They get all the water they need from the plants they eat. Kangaroo rats keep cool by coming out only at night to look for food. Ringtail cats also come out only at night. Ringtail cats hunt and eat kangaroo rats. Coyotes eat both the kangaroo rats and the ringtail cats.
Nothing is wasted in a food wed. Vultures eat dead animals. Vultures are scavengers. Scavengers do not hunt and kill other animals to get food. They eat animals that are already dead. When a ringtail cat or a coyote dies, it makes a meal for the vultures. Scavengers do an important job in keeping the environment clean.

31. Where does the energy that living things need first come from?
A. Animals.         B. Plants.       C. The sun.        D. Plant eaters.
32. Why do ringtail cats come out only at night?
A. Because they are afraid of coyotes.
B. Because they are shy animals.
C. Because it is very hot in the daytime.
D. Because they can eat kangaroo rats.
33. What kind of animal can be placed in the empty box of the picture?
A. Kangaroo.       B. Vulture.        C. Cat.       D. Zebra.
34. Which of the following is NOT TRUE according to the passage?
A. Lions eat different kinds of animals.
B. Plants are on the top of the food chain.
C. Scavengers can keep the environment clean.
D. Some animals get water from the plants they eat.
35. What’s the best title of the passage?
A. Web of life         B. Things that we eat
C. Food  in the desert    D. The place where food is from

答案解析

【主旨大意】本文是一篇说明文。介绍了自然界中食物链的构建和循环。
31. C解析：细节理解题。根据文中第一段第二句This energy comes first from the sun.，可知
生物最初需要的能量来源于太阳。
32. D解析：细节理解题。根据文中第五段句子Ringtail cats also come out only at night. 
Ringtail cats hunt and eat kangaroo rats. 可知圈尾猫仅在夜间出来是为了捕捉长鼻袋鼠吃。
33. B解析：细节理解题。根据文中最后一段中的When a ringtail cat or a coyote dies, it makes a meal for the vultures.可知秃鹰吃圈尾猫和北美小野狼。
34. B解析：推理判断题。根据第一段中的Plants use water and sunlight to make their own food. 
Animals can not make their own food, and they eat plants.可知植物不处于食物链的顶端。
35. A解析：主旨大意题。根据短文内容可知主旨大意是介绍了自然界中食物链的构建和循环。