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（葡萄糖）.Glucose is a kind of sugar. Plants use glucose as food for energy to grow. The way plants turn water and CO2 into glucose is called photosynthesis (光合作用).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 not 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, 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 is made from wastes left in the leaves.

The underlined word “chlorophyll” in the first Para means        in Chinese.

A  叶绿素           B 氧气          C 胡萝卜素      D 蛋白质

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.

The gas called carbon dioxide is from the         

A  ground      B roots        C air      D sunlight

Which of the following is not true?

A. when autumn and winter come, the days get shorter and shorter.

B. During winter trees rest and live on the food they store during the summer.

C. During winter small amounts of yellow and orange colors are kept in the leaves all the time.

D. Trees begin to stop making food in summer.

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（葡萄糖）.Glucose is a kind of sugar. Plants use glucose as food for energy to grow. The way plants turn water and CO2 into glucose is called photosynthesis (光合作用).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 not 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, 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 is made from wastes left in the leaves.

1. The underlined word “chlorophyll” in the first Para means        in Chinese.

A  叶绿素           B 氧气          C 胡萝卜素      D 蛋白质

2.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.

3.The gas called carbon dioxide is from the         

A  ground      B roots        C air      D sunlight

4.Which of the following is not true?

A. when autumn and winter come, the days get shorter and shorter.

B. During winter trees rest and live on the food they store during the summer.

C. During winter small amounts of yellow and orange colors are kept in the leaves all the time.

D. Trees begin to stop making food in summer.

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（葡萄糖）.Glucose is a kind of sugar. Plants use glucose as food for energy to grow. The way plants turn water and CO2 into glucose is called photosynthesis (光合作用).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 not 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, 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 is made from wastes left in the leaves.

52 the underlined word“chlorophyll” in the first Para means_________in Chinese.

A  叶绿素           B 氧气          C 胡萝卜素      D 蛋白质

53 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.

54 The gas called carbon dioxide is from the_________

A  ground      B roots        C air      D sunlight

55 Which of the following is not true?

A. when autumn and winter come, the days get shorter and shorter.

B. During winter trees rest and live on the food they store during the summer.’

C. During winter small amounts of yellow and orange colors are kept in the leaves all the time.

D. Trees begin to stop making food in summer.

We all enjoy the beautiful show of colors as leaves change each autumn. But did you ever wonder how and why this happens? To answer the question, first you have to understand what leaves are and what they do.

Leaves are nature’s food factories. Plants take water from the ground through their roots. And they take a gas called carbon dioxide from the air. Plants use sunlight to turn water and carbon dioxide into glucose (葡萄糖). Glucose is a kind of sugar. Plants use glucose as food for energy and as a building block for growing.

The way plants turn water and carbon dioxide into sugar is called photosynthesis (光合作用). That means, “putting together with light”.

A chemical called chlorophyll (叶绿素) helps photosynthesis. Chlorophyll is what gives plants their green color. As summer ends and autumn comes, the days get shorter and shorter. This is how trees “know” to begin getting ready for winter.

During winter, there is not enough light or water for photosynthesis. Trees rest during this time and live off the food they stored during the summer. They begin to shut down their food-making factories.

The green chlorophyll disappears from the leaves. As the bright green fades away, we begin to see yellow and orange leaves. Small amounts of these colors have been in the leaves all along. We just can’t see them in the summer, because they are covered up by the green chlorophyll.

The bright reds and yellows we see in leaves are made mostly in autumn. In some trees, like maples, glucose is caught in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn turn this glucose into a red color. The brown color of trees like oaks (橡树) is made from waste left in the leaves.

It is the mixture of all these things that makes the beautiful colors we enjoy during autumn.

36. Which of the following about chlorophyll is NOT true?

A. Without it photosynthesis couldn’t happen.

B. It is the reason why leaves have their green color.

C. It turns the leaves red during autumn.

D. It is a chemical that’s important for trees’ food making.

37. From the text we can see that photosynthesis _____.

A. can produce glucose, which can provide energy for trees’ growth

B. can happen whenever there is light and water

C. is the process of putting sunlight together with chlorophyll

D. doesn’t stop during the trees’ lifetime even in winter

38. What’s the author’s purpose of writing the passage?

A. To explain the process of trees’ photosynthesis.

B. To encourage readers to protect the environment.

C. To analyze the reasons why leaves change colors.

D. To help readers understand what leaves and trees are.

We all enjoy the colors of autumn leaves. Did you ever wonder how and why a fall leaf changes color? Where do the yellows and oranges come from? To answer those questions, we first have to understand what leaves are and what they do.

      Leaves are nature's food factories. Plants take water from the ground through their roots. They take a gas called carbon dioxide from the air. Plants use sunlight to turn water and carbon dioxide into glucose, which is a kind of sugar. Plants use glucose as food for energy and as a building block for growing. The way plants turn water and carbon dioxide into sugar is called photosynthesis, which means " putting together with light. " A chemical called chlorophyll helps make photosynthesis happen. Chlorophyll is what gives plants their green color.

      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 not enough light or water for photosynthesis. The trees will rest, and live off the food they stored during summer. They begin to shut down their food-making factories. The green chlorophyll disappears from the leaves. As the bright green fades away, we begin to see yellow and orange colors. Small a-mounts of these colors have been in the leaves all along. Covered up by the green chlorophyll, we just can't see them in summer.

     The bright reds and purples we see in leaves are made mostly in the fall. In some trees, like maples, glucose is trapped in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn cause the leaves turn this glucose into a red color. The brown color of trees like oaks is made from wastes left in the leaves.

     It is the combination of all these things that make the beautiful colors we enjoy in the fall.

The writer asked two questions in the beginning in order to        .

    A. persuade readers to believe something

    B. introduce the topic of the passage

    C. get the readers excited

D. offer something to think over

Which of the following is True according to the passage?

    A. Trees don't change colours with seasons.

    B. Trees can still perform photosynthesis well in winter.

    C. Trees have colours like yellow and orange even in summer.

D. Trees don't need food in winter.

Photosynthesis is a way that ___________________________.

A. plants change water and carbon dioxide into sugar

B. plants turn water and carbon dioxide into sugar with the help of sunlight

C. plants use glucose as food for energy and growing

D. chlorophyll is a great help

Which is the best title for this passage?

    A. Colorful trees in autumn            B. Mysteries of tree colors

C. Do you enjoy tree colors?           D. Wonderful colors in autumn