Discuss in pairs and answer the following questions.

1. What do you think of chewing gum? Is it good or bad for you?

2. Do you or your friends /family buy it? Why?

3. What do you do after chewing it?

Look at the title of the magazine article and predict which issues may be covered in the article. Then read the article quickly and see if any of your guesses are right?

It is about whether chewing gum is good

or bad for you.

Read the text quickly and divide it into four Read the text quickly and divide it into four parts , then summarize the main topic of each parts , then summarize the main topic of each part.part.

Part 1(paragrah --- )Part 1(paragrah --- )

Part 2(paragraph --- )Part 2(paragraph --- )

Part3(paragraph --- )Part3(paragraph --- )

Part4(paragraph --- )Part4(paragraph --- )

AAdvantagedvantage DDisadvantageisadvantage

Helping people:Helping people:

1.1.__________________ bad breath bad breath

2. ____________2. ____________ tooth detooth decaycay

3.3.______________weightweight

4. __________ 4. __________ smokesmoke

1.making digestions 1.making digestions

____________________________________

2. Causing feelings of 2. Causing feelings of

____________________________________

3. Leading to _________3. Leading to _________

____________________________

4. Making people 4. Making people neglect_____________neglect_____________

__________________________________________

1.1. How serious is the problem of bad breath?How serious is the problem of bad breath?

2.2. What is added to sugar-free chewing gum which What is added to sugar-free chewing gum which may help prevent tooth problems?may help prevent tooth problems?

3.3. According to one research project, what is one According to one research project, what is one way of burning 70 kilocalories?way of burning 70 kilocalories?

4.4. What would be the effect on the stomach of What would be the effect on the stomach of constant chewing?constant chewing?

5.5. What other activities are stated that are better than What other activities are stated that are better than chewing gum?chewing gum?

Match the conditional sentences in Match the conditional sentences in italics italics in in the text with the following types:the text with the following types:

1.1. zero conditionalzero conditional

2.2. 1st conditional1st conditional

3.3. 2nd conditional2nd conditional

4.4. 3rd conditional3rd conditional

Which of the sentences in italics talk about the past, the present and the future?

Read the sentences. Do they describe Read the sentences. Do they describe situations that are:situations that are:

a)a) True or could possibly happen?True or could possibly happen?

b)b) Imaginary, unreal or contrary to Imaginary, unreal or contrary to facts?facts?

If he has time, he will come.If he has time, he will come. We won’t succeed unless we plan well.We won’t succeed unless we plan well. (unless= if---not)(unless= if---not) 从句用一般现在时或现在完成时， 主句用一般从句用一般现在时或现在完成时， 主句用一般

将来时将来时

If I were a millionaire, I would buy a big If I were a millionaire, I would buy a big house.house.

If I were the girl in the story, I would call If I were the girl in the story, I would call the police at once.the police at once.

Tomorrow I will go to USA. If I were in Tomorrow I will go to USA. If I were in China, I would make dumplings with you.China, I would make dumplings with you.

表示与现在或将来事实相反表示与现在或将来事实相反从句从句 主句主句过去式过去式 would + Vwould + V 原原

I was on my own yesterday. If they had invited I was on my own yesterday. If they had invited me, I would have gone to the party.me, I would have gone to the party.

I went to library yesterday. If I had went to the I went to library yesterday. If I had went to the concert, I would have taken photos with the concert, I would have taken photos with the singers.singers.

He had traffic accident yesterday. If he had He had traffic accident yesterday. If he had driven more carefully, he would have arrived driven more carefully, he would have arrived home safely.home safely.

表示与过去事实相反表示与过去事实相反

从句从句 主句主句had donehad done would have donewould have done

如果过去天气好一些， 现在庄稼还会长得如果过去天气好一些， 现在庄稼还会长得更好。更好。

If the weather had been more If the weather had been more favourable, favourable, the crops would be growing the crops would be growing still better.still better.

(( 注意：白字代表过去， 注意：白字代表过去， 黄字代表现在或将黄字代表现在或将来来 ))

要是大夫昨晚来得早一点， 要是大夫昨晚来得早一点， Amy Amy 今天还活今天还活着。着。

If the doctor had come sooner last night, If the doctor had come sooner last night, Amy would be alive today.Amy would be alive today.

如果他多得六票， 他现在就是我们的主席。如果他多得六票， 他现在就是我们的主席。 If he had received six more votes, If he had received six more votes, he he

would be our chairman now.would be our chairman now.

与现在，将来事实相反与现在，将来事实相反 与过去事实相反与过去事实相反

从句从句 If + If + 主语主语 + + 过去式过去式 If + If + 主语主语 + had + had donedone

主句主句 主语主语 + would +V+ would +V 原原 主语主语 + would have + would have done done

从句从句 主句主句与现在与现在或将来或将来相反相反

If + If + 主语主语 + + 一般一般过去式过去式

主语主语 + would+ V+ would+ V 原原

与过去与过去相反相反

If + If + 主语主语 ++ 过去过去完成时完成时

主语主语 + would + have + would + have donedone

1. If you ____ at school, you ____ a college 1. If you ____ at school, you ____ a college student now.student now.

A. had studied hard; would have beenA. had studied hard; would have been B. should have studied hard; should have B. should have studied hard; should have

beenbeen C. had studied hard; would beC. had studied hard; would be D. would study hard; must have beenD. would study hard; must have been

2. ____ you ____ to the teacher, you ___ 2. ____ you ____ to the teacher, you ___ how to use the idioms now.how to use the idioms now.

A. Had, listened, would knowA. Had, listened, would know B. If, listen, knowB. If, listen, know C. If, had listened, would have knownC. If, had listened, would have known D. Had, listened, knowD. Had, listened, know

3. If he missed the bus, he _____ to school 3. If he missed the bus, he _____ to school on foot.on foot.

A. would go B. wentA. would go B. went C. would have gone D. had goneC. would have gone D. had gone

4. Had I known her name, ______.4. Had I known her name, ______. A. or does she know mineA. or does she know mine B. she would come hereB. she would come here C. I would have invited her to lunchC. I would have invited her to lunch D. she had comeD. she had come

5. ---Did you hear what Jack said to his 5. ---Did you hear what Jack said to his parents?parents?

---Yes, and I ____ talk that way if I ____ ---Yes, and I ____ talk that way if I ____ Jack.Jack.

A. won’t, am B. wouldn’t, wereA. won’t, am B. wouldn’t, were C. couldn’t, were D. didn’t, wereC. couldn’t, were D. didn’t, were

6. He ___ you if you ____ to see him this 6. He ___ you if you ____ to see him this afternoon.afternoon.

A. might tell, wentA. might tell, went B. might tell, are goingB. might tell, are going C. might have told, wentC. might have told, went D. should tell, will have goneD. should tell, will have gone

7. It ____ a different matter now if you ____ 7. It ____ a different matter now if you ____ his advice.his advice.

A. is, had followed B. was, followedA. is, had followed B. was, followed C. might be, had followed C. might be, had followed D. might be, followedD. might be, followed 8. The soldier died in the hospital. He ___ if 8. The soldier died in the hospital. He ___ if

the doctor ____ on him two hours before.the doctor ____ on him two hours before. A. might be saved, operatedA. might be saved, operated B. could have been saved, had been B. could have been saved, had been

operatedoperated C. could be saved, had operatedC. could be saved, had operated D. could have been saved, had operatedD. could have been saved, had operated

---If he ___, he ____ that food.---If he ___, he ____ that food. ---Luckily he was sent to the hospital ---Luckily he was sent to the hospital

immediately.immediately. A. was warned; would not takeA. was warned; would not take B. had been warned; would not have takenB. had been warned; would not have taken C. would be warned; had not takenC. would be warned; had not taken D. would have been warned, had not takenD. would have been warned, had not taken

I didn’t see your sister at the meeting. If I didn’t see your sister at the meeting. If she ____, she would have met my brother.she ____, she would have met my brother.

A. has come B. did comeA. has come B. did come C. came D. had comeC. came D. had come

You didn’t let me drive. If we ____ in turn You didn’t let me drive. If we ____ in turn you _____ so tired.you _____ so tired.

A. drove; didn’t get B. drove; wouldn’t getA. drove; didn’t get B. drove; wouldn’t get C. were driving; wouldn’t getC. were driving; wouldn’t get D. had driven; wouldn’t have getD. had driven; wouldn’t have get