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 CO2into 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? sunlight++CO2glucose

A.airB.sugarC.waterD.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

【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】B

【2】C

【3】A

【4】B

【5】D

【解析】

【1】考查細(xì)節(jié)推斷題。由短文第二段第三行...turn water and CO2into glucose.把水和二氧化碳變成葡萄糖，可知答案是C.

【2】考查詞義推測(cè)題。由短文第三段第一行... gives plants their green colour給植物綠的顏色，可知此題答案是A.

【3】考查細(xì)節(jié)推斷題。由短文第四段第一行 During winter, there is not enough sunlight or water.在冬季期間，沒(méi)有足夠的陽(yáng)光和水；和最后一行...we begin to see yellow and orange leaves. 我們開(kāi)始看到黃色和橙色的葉子，可知答案是C.

【4】考查綜合推斷題。綜合全文可知D是錯(cuò)誤的。

【5】考查主旨推斷題。綜合全文可推斷出主旨是不是所有的葉子的顏色都來(lái)自葉綠素。