Question

【題目】 Do you want to know how and why a fall leaf changes color? We first have to

understand what leaves are and what they do.

Leaves are the world’s food factories. Plants take water from the ground through their roots and take CO2 from the air. Plants use sunlight to turn water and CO2 into glucose(葡萄糖), a kind of sugar. Plants use it as food for energy and growing.

A chemical called “chlorophyll” in the leaves gives plants their green colour. As summer ends and autumn comes, the days get shorter and shorter, and trees “know” to begin getting ready for winter.

During winter, there is not enough sunlight or water. Trees rest during this time and live on the food they store during the summer. They begin to shut down their food-making factories. As the green chlorophyll disappears from the leaves, we begin to see yellow and orange leaves.

The bright reds and purples we see in leaves are made mostly in autumn. In some trees, like maples, sunlight and the cool nights of autumn turn the glucose in the leaves into a red colour. And we can enjoy the beautiful red leaves during autumn.

【1】Which should be in the box?

A. air B. sugar C. water D. wind

【2】The underlined word “chlorophyll” means __________.

A. 葉綠素 B. 脂肪 C.蛋白質(zhì) D.淀粉

【3】The leaves turn yellow because they are short of(缺少) __________.

A. water and CO2 B. glucose and energy

C. sunlight and water D. sunlight and CO2/p>

【4】Which of the following is NOT true?

A. When autumn comes, the days get shorter and shorter.

B. During winter trees live on the food they store in summer.

C. During winter some of yellow and orange colors are still in the leaves.

D. Trees begin to stop making food in summer.

【5】This passage tells us_____________.

A. the plants can grow well only with the sunlight

B. there are all kinds of plants on the earth

C. not all the colors of the leaves are from chlorophyll

D. maple leaves change the color as other trees

Answer 1

【答案】

【1】C

【2】A

【3】C

【4】D

【5】C

【解析】

試題分析：短文大意： 葉子是世界上的食品加工廠。植物通過自己的根從地面吸取水分，從空氣中吸收二氧化碳。植物利用陽光將水和二氧化碳轉(zhuǎn)化為葡萄糖。植物用它作為能源和食物�！叭~綠素”給植物的葉子綠顏色。

【1】C細節(jié)理解題。根據(jù)第二段中Plants use sunlight to turn water and CO2 into glucose(葡萄糖), a kind of sugar.可知植物利用陽光將水和二氧化碳轉(zhuǎn)化為一種葡萄糖，所以該選C。

【2】A詞義猜測題。根據(jù)后面的gives plants their green colour可知“chlorophyll”是葉綠素，所以該選A。

【3】C細節(jié)理解題。根據(jù)第四段中During winter, there is not enough sunlight or water. Trees rest during this time and live on the food they store during the summer. They begin to shut down their food-making factories. As the green chlorophyll disappears from the leaves, we begin to see yellow and orange leaves.的描述可知葉子變黃是因為缺少陽光和水，所以該選C。

【4】D細節(jié)理解題。根據(jù)生活常識可知在冬天樹葉都落啦，所以該選D。

【5】C細節(jié)理解題。根據(jù)文中描述可知葉綠素使葉子為綠色，但并不是所有的葉子的顏色都來自葉綠素，所以該選C。