Question

    A food chain is a simple way of explaining how each living thing gets its food. For example, a simple African food chain might consist of three parts: first, trees and bushes; second, giraffes; and third, lions. Each link in a food chain is food for the next link. Food chains always start with plants and end with animals.

Plants are at the bottom of the food chain. Scientists call them producers, because they use light energy from the sun to produce food from carbon dioxide and water through photosynthesis（光合作用）. Animals, unlike plants, can’t produce their own food. Instead, they must eat plants or other animals. This is why scientists call them consumers.

Consumer animals fall into three categories. Herbivores（食草动物）eat only plants. Carnivores（食肉动物） eat only other animals. Omnivores eat both plants and animals. In addition to producers and consumers, there are also decomposers(分解者).These organisms, such as bacteria and fungi, feed on decaying(腐烂) matter. They help the food chain by speeding up the decaying process that releases minerals back into the soil to be absorbed by plants as nutrients.

Most food chains have only four or five links in them. As you go up a food chain, the amount of energy at each level diminishes, because some of the energy is lost in the form of waste or is used up by the organism at the level. That is why it takes many plants, for example, to feed a few giraffes who in turn feed one lion.

Most animals are part of many different food chains, because they must eat more than one type of food to satisfy their energy needs. All of these interconnected food chains form a more complex structure called a food web. Humans, for example, are at the center of a very complex food web, because we tend to eat many different types of plants and animals.

1.Which of the following tells us the African food chain?

A. Trees, giraffes and lions live on one another.

B. Giraffes eat lions and lions feed on bushes.

C. Lions live on giraffes and giraffes eat trees.

D. Bushes live on lions and lions eat giraffes.

2.In the second paragraph,the author is mainly to         .

A. emphasize the importance of the plants

B. compare the plants and the animals

C. present the scientists’ different views

D. explain the producers and consumers

3.The underlined word “diminishes”（in Paragraph 4）probably means         .

A. changes B. decreases

C. disappears D. increases

4.Those that may lie in the center of the food chain are          .

A. omnivores B. decomposers

C. herbivores D. carnivores

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

A. The Types of Plants and Animals

B. The Differences among the Living Things

C. Three Categories of the Consumers

D. The Food Chain in the Natural World

Answer

1.C

2.D

3.B

4.A

5.D

【解析】

本文是一篇说明文。文章以食物链为话题，分析说明了自然界中动植物相互依存的关系，并提出了食物链中的主体——食草动物、食肉动物和草肉皆食动物。

1.细节理解题。根据文章第一段中的最后两句“Each link in a food chain is food for the next link.Food chains always start with plants and end with animals.”可知，非洲食物链的依存关系。

2.主旨大意题。很明显本段中主要介绍了食物链中的生产者和消费者。

3.词义猜测题。根据下文中的“...because some of the energy is lost in the form of waste or is used up by the organism at that level.”可以推知，该词的意思是“减少”。

4.推理判断题。根据第三段第四句和最后一段作者所列举的例子可知，既食草又食肉的动物位于食物链的核心。

5.主旨大意题。本文主要讲述了大自然中的食物链。

高频词汇

herbivore n. [动] 食草动物

carnivore n. [动] 食肉动物

omnivore n. [动] 杂食动物；不偏食的人

interconnect v. 互相联系

【长难句分析】 Most animals are part of many different food chains，because they must eat more than one type of food to satisfy their energy needs.大多数动物是许多不同食物链的一部分，因为它们不只吃一种食物以满足自己的能量需求。该句为复合句。句中because引导原因状语从句。另外，more than one意为“许多”；satisfy意为“使满足”。