握派生规律对扩充词汇有很大帮助。例如： 由 interest 可以派生出： uninteresting interest — interesting — interestingly interested — uninterested 由 help 可以派生出： helpless — helplessly help — helpful — helpfully 由 able 可以派生出： enable able unable ability disable 3. 转化法 英语构词法中把一种词性转化为另一种词性而词形不变的方法称作转化法。常见的转化有： (1) 动词转化为名词 — Let’s talk about it more. 咱们再谈谈这件事吧。 — I think we’d better finish the talk now. 我想我们最好现在结束谈话。 (2) 名词转化为动词 She gave me a cup of water. 她给了我一杯水。 You should water the flowers twice a day. 你应该每天给这些花浇两次水。 (3) 形容词转化为名词 She was wearing a black dress. 她穿着一条黑色的裙子。 The girl in black looks very beautiful. 那个穿黑衣服的女孩看上去很漂亮。
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Chapter 4 Effective practice, consolidate the knowledge(训练巩固) Step 6 Exercises Complete the sentences with the words in the box. hopeful impossible reuse unhealthy wasteful 1. Polluted water is ____________. 2. It is _________ to throw so much food away. 3. If you look after things well, you may ________ some of them later. 4. It is ___________ to clean up the whole river in such a short time. 5. If we pay attention to pollution now, the future will be __________. Step 7 Complete the table. Noun hope pollution water waste —— Verb —— Adjective useful/useless —— Adverb hopefully / hopelessly —— —— usually/unusuallyStep 8 Complete the sentences with the correct form of the words in Activity 3. She was hopeful that her new job would make her more successful. 1. The factory ___________ the river, and the fish died. 2. We often walk in the countryside. It is a(n) _______ activity for us. 3. Do not use so much water. It is very __________. 4. To keep the flowers growing, you need to _________ them once a day. Step 9 Complete the sentences. A lunchbox is a box that you keep your lunch in. 6 1. A ___________ is a card that you write on one side of and send to someone by post. 2. A ___________ is a room where you have classes at school. 3. A ___________ is a book that has one or more stories for children. 4. A ____________ is a black board that is used at school for writing on with chalk. Step 10 Work in pairs Look at the pictures and answer the questions. 1. What kinds of things can be recycled? 2. How can these things be reused? 3. How does this help the environment? 4. Have you ever recycled or used things that can be recycled? How? Step 11 Complete the conversation with the correct form of the expressions in the box. be good for throw away turn off worry about Mike: I hear you are off to the Caribbean for a holiday! Lucky you! But aren’t you _____________ the pollution that such long plane journey may cause for the environment? Ken: I know, but what can I do about it? I’ve already tried my best to protect the environment. I recycle. I don’t ____________ things if I don’t want them any more. I __________ the lights when I leave a room. Don’t tell me I shouldn’t travel by plane any more! Mike: No, of course not. But we can do more to protect the environment. For example, we can help keep the air clean by planting trees. Trees ______________ the environment. In this way, we can reduce the harm of pollution. Ken: Good! So I can enjoy my holiday, and when I come back, I’ll
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plant some trees! Mike: That’s the idea! Maybe we can all join in and start a small forest! Step 12 Listening Listen and check (√) the true sentences. a) Do not throw away things made of glass, plastic and paper, but recycle them when possible. b) Take a bag when you go shopping. c) It is OK to throw used things away. Looking after them takes a lot of time. d) Turn off lights when you do not need them. e) Ride a bike or walk, and do not often drive your car. f) Paper cups and bottled drinks make our life easier. We can use them as much as possible. Step 13 Listen again and complete the table. Advice 1. Don’t throw away things made of _________, but _______ them. Reasons Throwing things away is wasteful. 2. __________ your plastic bags when Plastic bags __________ you can and __________ with you when recycle. you go shopping. 3. Use less electricity and oil to _________. 4. Don’t leave lights on and __________. 5. ________ and do not often drive your car. Chapter 5 Summary evaluation, leak turnover(总结评价，查漏补缺) Step 14 Around the world Producing electricity and using oil may cause ___________.
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