英國大使館文化教育處

Read a conversation between a biology student and his friend.

So， Simon， youre studying biology. Can you explain a littlebit about it？

Biology is about all the things on our world that are alive—plants，animals， as well as very small living things that we cannot see.Biology tries to explain why life is like it is.

It sounds complicated. There are so many different kinds ofplants and animals.

Thats true. Different kinds of plants and animals can look verydifferent. But they usually keep alive in the same way. For example，nearly all plants photosynthesize. This is how they get their energy.If we understand photosynthesis， then it makes things a lot moresimple.

Photosynthesis. I remember studying this at school. I dontthink I understand it very well.

Well， I will try and explain. Plants take light from the sun， aswell as water from rain and rivers， and carbon dioxide from the air.Carbon dioxide is a type of gas that people and animals make whenthey breathe. Inside the green parts of each plant is something called“chlorophyll”. This helps the plant to make sugar using light， waterand carbon dioxide. Then the plant uses the sugar to make energy，so it can grow.

Why is it so important？

Before photosynthesis， there were no plants， flowers， trees，animals or people—just an empty world with only very small livingthings that we cannot see.

Did it help animals and people then？

Yes， by making oxygen. Oxygen is the gas that keeps youand me and every other human alive. We breathe in oxygen and itkeeps our hearts going. But it is photosynthesis that makes oxygen.

Oxygen？ You didnt say oxygen earlier.

Thats because it is not used by plants. It is made by themduring photosynthesis but they dont need it. We do.

Wow. Thats lucky. Thanks， plants！

Activity 1 Complete the sentences

Look at the following “word family”. These words have the samemeanings but their grammar is different.

a. alive b. live c. life

Complete each sentence below using one of these words.

1. People who eat healthy food ________ for a long time.

2. She had a very bad accident. Its very lucky shes still ________.

3. He died when he was 96 years old. He had a long and interesting ________.

Activity 2 Look at the words below （a–d） and complete the sentences（1–4）.

a. complicated b. breathe c. energy d. light

1. If something is ________， it is difficult to understand.

2. Do exercise， you need ________.

3. When you ________， you take air into your body.

4. The sun makes the world warm and gives it ________.

Activity 3 Complete the sentences below using the words in the list （a–e）.

a. humans b. breathe c. oxygen d. light e. energy

Photosynthesis is one of the most important things that happen in theworld. Plants use 1. ________， water and carbon dioxide to make sugar. Thissugar then gives them the 2.________ they need to grow. Photosynthesis isalso important for 3.________ . Because it makes 4.________ ， which we need to5.________ . Without photosynthesis， humans and animals cannot live.

參考答案：

Activity 1 1. b; 2. a ; 3. c

Activity 2 1. a; 2. c; 3. b; 4. d

Activity 3 1. d; 2. e; 3. a; 4. c; 5. b