Unit 4, Book I

1. Unit 4, Book I 郧阳师专英语系综合英语教研室

2. Language Structures • Grammar Points: • There are nine modal verbs in English: can, may, will, shall, dare, must, ought to, need, used to, of which some both have present tense and past tense, and some only have its present tense or past tense. • Today we are going to talk about some usages of some modal verbs:

3. The Usage of Can 1. Can Jane sing well? Was she able to / Could she sing so well a year ago? Will she be able to sing even better next year? • Modal verbs can / could and be able to used in the above sentences to express one’s ability in doing something. • “Can” used to express the present ability and future ability; it may refer to the concrete ability of doing something, or the common ability. Egs: I canclimb this cliff. (concrete) Is there anything I can do for you? He can drive a car. (common) He can read and write.

4. The Usage of Be Able to • If we want to express one’s ability in the future, we usually use “will / shall be able to”. E.g. I’ll be able to speak Japanese in another two months. • If we want to express one’s ability of doing some concrete things in the future, we may use “can”. Egs: Can you go and see him tomorrow morning? If I can, I will do it.

5. Couldandwas / were able to are usually used to express one’s ability in the past. But in affirmative sentences, “could” only refers to one’s common ability in the past. E.g.: She could play the piano when she was only six. • We only can use “was / were able to, managed to” when we want to express one’s ability of doing some concrete things in the past. Egs: He was able to swim halfway before he collapsed. He was able to translate the article without a dictionary. I talked a long time, and in the end I managed to make her believe me.

6. Could VS Be Able to • What we have talked about the usages of could and was / were able to are only referring to the affirmative sentences, but in the negative sentences there is no such limitations. That is to say, in negative sentences we can use “could” to express one’s common ability and concrete ability of doing something in the past. Egs: I couldn’t / wasn’t able to play the piano when I was at school. He got so drunk that he couldn’t / wasn’t able to find the front door.

7. The differences between “can” and “be able to” (I) • When we want to express one’s ability (esp. the things only to be finished by some kind of knowledge or skill), we may use both “can” and “be able to”. 1) In future tense and perfective tense, “be able to” is used. 2) If it is some concrete thing that was successfully finished by a hard effort, we may only use “be able to” or “manage to”.

8. The differences between “can” and “be able to” (II) 3) In some idioms, such as can’t help, couldn’t help, the words “can’t” and “couldn’t” can’t be changed into “be able to”; because “can’t help, etc.” refer to some unconscious behavior, but “be able to” is often used to express the conscious one. 4) When “be able to” was used in the sentence as predicative, the subject should only be the person, and it can’t use in the passive voice.

9. A: Do you have to live on the campus now? B: Yes, I do. A: Did you have to live on the campus last year? B: No, I didn’t have to then. A: Will you have to live on the campus next year? B: Yes, I shall still have to. 1) Have to, like must, is used to express obligation and necessity. Must has only one form and it is used for all persons in the present and future. Have to, however, is almost like a full verb and has present, past, and future forms. In meaning, there are some differences between must and have to. Must expresses an obligation imposed by the speaker while have to expresses an obligation imposed by external circumstances.

10. For examples: ① Teacher to her students: You must get up early and read English aloud every morning. ② As Mary lives quite far away from where she works, she has to get up early every day. • The negative forms of have to in the present, past and future are doesn’t / don’t have to, didn’t have to and won’t have to respectively. 2) The affirmative short answers for have to in the present, past and future are: Yes, I do / have to, Yes, I did /had to, and Yes, I will / will not have to respectively.

11. 3. A: Can / May I be excused from the lecture this week, please? B: No, you can’t / may not. 1) Both can and may in the above sentences express “permission or request for permission”. If we want to ask for another’s permission, we can use: can, could, may, might. • May / might is used on more formal occasions and more polite while can / could, which is more often used, is for informal situations.

12. 2) If we want to give permission, we usually use can / may, but not could / might. Egs: A: “Could I use your phone?” B: “Yes, of course you can.” A: “Might I trouble you for a light?” B: “You may indeed.” 3) If we are not agree with the requirement that is raised by the others, we can use may not or can not. Please notice that the past form of may not is not might not, but usually transformed into other expressions: was / were not allowed to, didn’t permit. 4) Can I be excused from … is used to ask for permission to be freed from doing something. The Chinese equivalent of the first sentence given above is: 我不能不参加本星期的讲座吗？

13. 4. Could you tell me how a Xerox machine works? • Could you…? is a very useful request form. It is an alternative to Would you…? and is a little more polite than Would you…? Like Would you …?, Could you…? is past in form but has present reference.

14. 5. You’d better consult an encyclopaedia. --- You had better consult … • The meaning is: I’d advise you to consult …Hadhere is an unreal past, but the phrase had better refers to either the present or the future. Had better… is a very useful advice form. The negative is formed with not after better, e.g., => You had better not drink so much. Drinking is harmful to your health. • Modal verb had better expressing advice or suggestion. It can’t be used in the affirmative question, but only in negative question, e.g., => Hadn’t we better stop now?

15. Reading I A Source of Energy

16. Warm-up • How many sources of energy do you know? Traditional sources of energy: petroleum, oil, gasoline, gas, electrical energy, diesel oil, coal, wood, water energy, wind energy, animal energy New sources of energy: natural / marsh gas, nuclear energy, garbage, biomass, geothermal energy, solar energy, renewable energy, cow manure 2. Can you imagine the life without energy?

17. Specific Questions for Text • In what ways does solar energy help us? • How can water energy be used? • What can the power of winds do? • How are coal and oil used? • Why are people trying to find new sources of energy? • What do you think is the most popular source of energy used at present?

18. Language Points • source (n.) ① a place, person or thing that you get sth. from 来源，出处 ② [pl.] a person, book or document that provides information, especially for study, a piece of written work or news 信息来源，原始资料 ③ a person or thing that causes sth, especially a problem 起源，根源，原因 ④ the place where a river or stream starts 源头，发源地 E.g. the source of Yellow River all source of sorrow and pain a new source of income

19. resource (n.) ① [usu. pl.] a supply of sth that a country, an organization or a person has and can use, especially to increase their wealth 资源；财力 HUMAN RESOURCES ② something that can be used to help achieve an aim, especially a book, equipment, etc. that provides information for teachers and students 有助于实现目标的东西；资料 ③ [pl.] personal qualities such as courage and imagination that help you deal with difficult situations 勇气；才智；谋略

20. 2. convert (v.) convert (sth) (from sth) into/to sth To change or make sth change from one form, purpose, system, etc. to another E.g. 那家旅馆将被改建成私人疗养院。 The hotel is going to be converted into a nursing home. 我们已由燃煤改换成燃气集中供暖。 We’ve converted from coal to gas central heating.

21. 3. cart: two-wheeled vehicle for carrying heavy loads pulled by horses or oxen wagon: four-wheeled vehicle for carrying heavy loads pulled by horses or oxen vehicle: a thing that is used for transporting people or goods from one place to another, such as a car or lorry/truck 交通工具；车辆

22. 4. be used to do sth be used to sth / doing sth used to do sth 用于做某事 习惯于做某事 过去常常做某事

23. 5. mechanical (adj.) ① operated by power from an engine 机动的；机械驱动的；机械的 E.g. 抛锚是机械故障造成的。 The breakdown was due to a mechanical failure. ② (of people’s behaviour and actions) done without thinking, like a machine 机械般的；呆头呆脑的；无思想的 E.g. 我的工作已经变得机械呆板 --- 我睡着了都能做。 My work has become mechanical --- I could do it in my sleep.

24. 6. create (v.) creation (n.) creative (adj.) ① to make sth happen or exist 创造；创作；创建 E.g. 政府计划为年轻人创造更多的就业机会。 The government plans to create more jobs for young people. ② to produce a particular feeling or impression 造成；引起；产生（感觉或印象） E.g. 这家公司正试图塑造一个充满活力的年轻形象。 The firm is trying to create a young energeticimage.

25. 7. grind (v.) (ground, ground) grind sth down/up; grind sth to/into sth =>To break or crush sth into very small pieces between two hard surfaces or using a special machine 磨碎；碾碎；把…磨成粉 E.g. 他把香烟按在烟灰缸里捻灭。 He ground his cigarette into the ashtray. 这面粉是用传统方法磨制而成的。 The flour is ground using traditional methods. 她睡觉时磨牙。 She grinds her teeth when she is asleep.

26. 8. manure (n.) The waste matter from animals that is spread over or mixed with the soil to help plants and crops grow 肥料；粪肥 (verb) to put manure on or in soil to help plants grow 给…施肥

27. 9. promising (adj.) showing signs of being good or successful = hopeful 有希望的；有前途的；有出息的 E.g. 他因在电影中扮演的角色而被评为最有前途的新人。 He was voted the most promising newcomer for his part in the movie. 天气看起来不会太好。 The weather doesn’t look very promising.