题文

阅读材料，然后从各小题所给的四个选项中选出最佳选项。

Leaves are nature's food factories. Plants take water from the ground through their roots. They take a gas called carbon dioxide (CO2) from the air. Plants use sunlight to turn water and CO2 into glucose. Glucose is a kind of sugar. Plants are glucose as food for energy to grow. The way plants turn water and CO2 into glucose is called photosynthesis. That means "putting together with light". A chemical called chlorophyll helps make photosynthesis happen. Chlorophyll is green. It gives plants their green colour.          As summer ends and autumn comes, the days get shorter and shorter. This is how the trees "know" to begin getting ready for winter.          During winter, there is now enough light or water for photosynthesis. The trees will rest, and live on the food they have stored during the summer. They begin to close their food-making factories. The green chlorophyll disappears from the leaves. Then, we begin to see yellow and orange colours. A few of these colors stay in the leaves all the time. We just can't see them in the summer, because they are covered up by the green chlorophyll.                   Red and purple colors we see in leaves are made mostly in the autumn. In some trees, like maples (枫树), glucose is stored in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn turn this glucose into red. The brown color of trees like oaks (橡树) is made from wastes left in the leaves.

1. The word "chlorophyll" in the first paragraph means ____ in Chinese.

[     ]

A. 叶绿素 B. 氧气 C. 胡萝卜素 D. 蛋白质

2. Where is CO2 from?

[     ]

A. Ground. B. Roots. C. Sunlight. D. Air.

3. The way ______ is called photosynthesis.

[     ]

A. plants get CO2 from the air B. plants take water from the ground C. plants turn water and CO2 into glucose D. plants use glucose as food for energy to grow

4. Red and purple colors in leaves are made mostly in _______.

[     ]

A. spring B. autumn C. summer D. winter

5. _______in the leaves changes into red color in autumn.

[     ]

A. Sunlight B. Water C. Glucose D. Chlorophyll

题型：阅读理解  难度：偏难

答案

1-5 A D C B C

据专家权威分析，试题“阅读材料，然后从各小题所给的四个选项中选出最佳选项。 Leaves ..”主要考查你对  科教类阅读  等考点的理解。关于这些考点的“档案”如下：

科教类阅读

考点名称：科教类阅读

• 科普类的阅读：
  科普类的阅读理解包含介绍科学知识、社会知识的短文。阅读这类短文时，要以事实为中心进行思考，抓住事物的特征、用途、相互关系等。
  如果是介绍社会现象的文章，要掌握所谈现象的内涵。

• 答题技巧：
  1. 加强整体意识，把握文章的主要内容。在阅读的时候可给段落标上序号，并给重要的句子和
     关键词做上记号，尤其是各段中心句，为答题提供更快捷更多的信息源。
  2. 审清题干，发觉和把握试题中有效的提示性信息，确认命题的角度、阅读范围和答题方式。
  3. 定位阅读，强化对应意识。同时要注意原文利用和自我加工相结合。