It is bad to have food stuck between your teeth for long periods of time. This is because food attracts germs; germs produce acid, and acid hurts your teeth and gums. Flossing (使用牙線) helps to remove the food that gets stuck between your teeth. This explains why flossing helps to keep your mouth healthy, but some doctors say that flossing can also be good for your heart.

It may seem strange that something you do for your teeth can have any effect on your heart. Doctors have come up with a few ideas about how flossing works to keep your heart healthy. One idea is that the germs that hurt your teeth can leave the mouth and travel into your blood.Germs that get into the blood can then attack your heart. Another idea is based on the fact that when there are too many germs in your mouth, the body tries to fight against there germs. For some reason, the way the body fights these mouth germs may end up weakening the heart overtime.

Not every doctor agrees about these ideas. Some doctors think that the link between good flossing habits and good heart health is only a coincidence. The incidence (發(fā)生率) of two or more events is completely random, as they do not admit of any reliable cause and effect relationship between them. For example, every time I wash my car, it rains. This does not mean that when I wash my car, I somehow change the weather. This is only a coincidence. Similarly, some doctors think that people who have bad flossing habits just happen to also have heart problems, and people who have good flossing habits just happen to have healthy hearts.

The theory that flossing your teeth helps to keep your heart healthy might not be true. But every doctor agrees that flossing is a great way to keep your teeth healthy. So even if flossing does not help your heart, it is true to help your teeth. This is enough of a reason for everyone to floss their teeth every day.

1.From the passage, we know that ________.

A. food stuck between your teeth may hurt your teeth

B. all of the doctors agree that flossing is good for your heart

C. doctors’ judgment about flossing is based on medical research

D. not every doctor thinks flossing helps to keep your teeth healthy

2.The underlined sentence in Paragraph 3 is to ________.

A. provide an example

B. make a comparison

C. introduce a new topic

D. develop the previous statement

3.Which of the following best states the main idea of the last paragraph?

A. It is a fact that flossing can help your heart as well as your teeth.

B. There is no good reason to believe that flossing will help your heart.

C. Because doctors find flossing won’t help your heart, it is useless to floss.

D. Even if flossing is only good for your teeth, you should still do it every day.

4.Which is the best title for the passage?

A. Flossing by Coincidence

B. How to Keep Your Teeth Healthy

C. Flossing Habits and Healthy Hearts

D. Why Doctors Disagree About Flossing

練習冊系列答案
相關(guān)習題

科目：高中英語 來源：2016-2017學年江蘇南通中學高二12月考英語試卷（解析版） 題型：單項填空

—You could have asked Mrs Zhang for advice, for she is an expert at it.

—Yes, a whole day ________.

A. will be wastedB. would be wasted

C. had been wastedD. was wasted

查看答案和解析>>

科目：高中英語 來源：2016-2017學年浙江紹興一中高二上期中考試英語試卷（解析版） 題型：完形填空

閱讀下面短文，從短文后各題所給的四個選項(A、B、C、D)中，選出可以填入空白處的最佳選項。

A Person Who Has Influenced My Life

There is always a time in one’s life when a hero comes along. Someone who has inspired you can really help you learn what life is about.

I ____ it as if it was yesterday. I was fifteen years old that year. It was around eight o’clock one evening when my mother ____ a phone call from her brother-in-law, who told us my aunt was in hospital and that the doctor ____ them she would need an operation immediately. My family became very ____ about my aunt’s situation.

While my aunt was in the hospital with special ____, my cousin Mark, who is mentally disabled, spent time with my family. Mark was seventeen at the time, and had been born with severe mental disorders, which ____ a wide range of social and physical problems for him throughout everyday life. He never had any true friend ___ no one could relate to him. I must ____ that at the beginning I was filled with uncertainty as to how much of a ___ my cousin would bring on my family. Now looking back it saddens me to see the ___ I once showed.

Over the two weeks when Mark lived with my family, I probably ____ more about life and its meanings. Thinking back, I took ____ in daily life for granted, believing it would always be there. I never even thought about being able to do things like walking, brushing my teeth, or going to the bathroom on my own. Now I see how ____ I am to be able to do these things independently.

Mark was seventeen, but learned on a nine-year-old ____. Although his learning ability was slower than most, he could still learn. He explored ____ to do most of the things everyone else did. ____ he did pretty well and succeeded in almost everything he tried to do. He ____ his illness and showed an ambition to love life. To him, having a successful life means achieving goals on his own terms and at his own ____.

Mark is my hero, for his disability has forever ____ my viewpoint on life. It seems like a well-deserved life when you’re fifteen, and it is amazing how in a period of time your point of view can change so ____.

1.A. acceptB. rememberC. imagineD. discover

2.A. madeB. missedC. receivedD. used

3.A. promisedB. informedC. showedD. begged

4.A. curiousB. sureC. disappointedD. worried

5.A. careB. actionC. purposeD. interest

6.A. createdB. facedC. foundD. influenced

7.A. unlessB. althoughC. untilD. because

8.A. believeB. regretC. admitD. decide

9.A. puzzleB. failureC. burdenD. conflict

10.A. weaknessB. ignoranceC. reliefD. mercy

11.A. understoodB. dreamedC. questionedD. required

12.A. anythingB. somethingC. nothingD. everything

13.A. powerfulB. braveC. luckyD. successful

14.A. varietyB. levelC. jobD. balance

15.A. possibilitiesB. functionsC. achievementsD. difficulties

16.A. TypicallyB. OccasionallyC. AccidentallyD. Actually

17.A. challengedB. preventedC. treatedD. reported

18.A. businessB. costC. paceD. request

19.A. representedB. changedC. formedD. supported

20.A. easilyB. normallyC. properlyD. completely

查看答案和解析>>

科目：高中英語 來源：2017屆江西上高縣二中高三上期第五次月考英語試卷（解析版） 題型：完形填空

A policeman was walking along the street. In the doorway of a shop, a man was standing in the ________ light, with an unlighted cigar in his mouth. The policeman ________ and then walked up to the man.

“I’m just waiting for a friend here,” the man said “It’s a(n) ________ made twenty years ago.” The man struck a match and ________ his cigar. The light ________ a pale face with a little white scar(疤) near his right eye. “Twenty years ago tonight, when I said goodbye to Jimmy Wells, my best friend to ________ for the West to make my fortune, we ________ we would meet here again exactly twenty years ________ that date and time.” “I hope your friend will come around soon.” said the policeman, ________.

Twenty minutes later, a(n) tall man hurried across the street. He went directly to the waiting man. “Is that you, Bob?” he asked. “Jimmy Wells?” ________ the man with excitement. “You have ________, Jimmy. I never thought you were so tall.”

When they both looked at each other ________, the man said suddenly “You’re not Jimmy Wells. Twenty years is a long time, ________ not long enough to change a man’s ________.” “It sometimes changes a good man into a ________ one,” said the tall man. “You are under ________ now. Well, here is a note from your friend.” His hand was steady when he began to read, but it ________ a little by the time he had finished. It reads: “Bob: I was at the appointed place ________. When you lighted your cigar I saw it was the face of the man ________ by Chicago police. ________ I couldn’t catch myself, so I went around and got a plain clothes man to do the job.”

1.A. darkB. brightC. dimD. colorful

2.A. slowed downB. picked outC. went onD. hurried up

3.A. mistakeB. timeC. tradeD. appointment

4.A. stoppedB. lightedC. burntD. dropped

5.A. formedB. appearedC. relievedD. showed

6.A. startB. workC. lookD. search

7.A. insistedB. preferredC. agreedD. suggested

8.A. forB. fromC. laterD. at

9.A. speeding upB. coming toC. pulling offD. moving away

10.A. criedB. smiledC. weptD. choked

11.A. grewB. achievedC. changedD. became

12.A. clearlyB. surprisinglyC. quicklyD. happily

13.A. butB. andC. orD. while

14.A. characterB. faceC. qualityD. size

15.A. successfulB. ordinaryC. tallD. bad

16.A. discussionB. controlC. arrestD. inspiration

17.A. trembledB. struggledC. escapedD. understood

18.A. in advanceB. on time

C. before longD. sooner or later

19.A. askedB. wantedC. describedD. caught

20.A. AnywhereB. ThoughC. HoweverD. Anyway

查看答案和解析>>

科目：高中英語 來源：2017屆內(nèi)蒙古高三上第三次模擬考試英語試卷（解析版） 題型：短文改錯

假定英語課上老師要求同桌之間交換修改作文，請你修改你同桌的以下作文。文中共有10處語言錯誤，每句中最多有兩處，每處錯誤僅涉及一個單詞的增加、刪除或修改。

增加：在缺詞處加一個漏字符號（∧）,并在其下面寫出該加的詞。

刪除：把多余的詞用斜線（\）劃掉。

修改：在錯詞下劃一橫線，并在該詞下面寫出修改后的詞。

注意：1. 每處錯誤及其修改均僅限一詞；

2. 只允許修改10處，多者（從第11處起）不計分。

This morning on my way to school I was deep moved by what I saw outside a bank. An old man was counting his money in the front of the bank. Suddenly a young man came running and knocked him down. To make things bad, his money was flying in all direction. In no time the people around rush to pick the money up while the old man stood there, not know what to do. Surprisingly, everyone gave back the money they had just picked up. The old man counted the money again and found that not a single bill was missed. To my great joy, there are now a lot nice people in your life. It’s true what honesty is more important than money!

查看答案和解析>>

科目：高中英語 來源：2016-2017學年西藏林芝地區(qū)一中高二上期末考試英語卷（解析版） 題型：語法填空

閱讀下面材料，在空白處填入適當?shù)膬?nèi)容（1個單詞）或括號內(nèi)單詞的正確形式。

A young man, while traveling through a desert, came across a spring of clear water. ___1.__water was sweet. He filled his leather container so that he could bring some back to elder __2.__ had been his teacher. After a four-day journey, the young man __3._ (present) the water to the old man. His teacher took a deep drink, smiled ___4.__ (warm), and thanked his student very much for the sweet water. The young man went home __5.__ a happy heart.

After the student left, the teacher let __6.___ student taste the water. He spit it out, __7.__ (say) it was awful. Apparently, it was no longer fresh because of the old leather container. He asked his teacher, “Sir, the water was awful. Why did you pretend to like __8._?”

The teacher replied, “You tasted the water. I tasted the gift. The water was simply the container for an act of kindness and love. Nothing could be __9.__ (sweet).”

We understand this lesson best ___10.___ we receive gifts of love from children. Whether it is a cheap pipe on a diamond necklace, the proper response is appreciation. We love the idea within the gift rather than the thing.

查看答案和解析>>

科目：高中英語 來源：2016-2017學年西藏拉薩北京實驗中學高一上期末英語卷（解析版） 題型：短文改錯

假定英語課上老師要求同桌之間交換修改作文，請你修改你同桌寫的以下作文。文中共有10處語言錯誤，每句中最多有兩處。每處錯誤僅涉及一個單詞的增加、刪除或修改。

增加：在缺詞處加一個漏字符號(∧)，并在其下面寫出該加的詞。

刪除：把多余的詞用斜線(\)劃掉。

修改：在錯的詞下劃一橫線，并在該詞下面寫出修改后的詞。

注意：1. 每處錯誤及其修改均僅限一詞；

2. 只允許修改10處，多者(從第11處起)不計分。

Today I visited the Smiths--my first time visit to a American family. They live in a small town. It was very kind for them to meet me at the railway station and drove me to their home. The Smiths did his best to make me feel at home. They offered me coffee and another drinks. We have a good time talking and laughing together. They eager to know everything about China and asked me lots of question. In fact, they are planning to visit China in next year.

查看答案和解析>>

科目：高中英語 來源：2016-2017學年湖北宜昌一中高二12月考英語試卷（解析版） 題型：書面表達

假定你是李華，你的英國筆友正在寫一篇關(guān)于各國中學生課外閱讀(extra-curricular reading)情況的調(diào)查報告，她給你發(fā)了一封電子郵件，想了解相關(guān)情況。請你根據(jù)以下提示，給他回一封電子郵件。

1. 你校學生課外閱讀的現(xiàn)狀；

2. 原因分析；

3. 你的看法；

注意：1.根據(jù)所給提示，適當發(fā)揮，要求內(nèi)容充實，語意連貫。

2.字數(shù)不少于100。開頭和結(jié)尾已經(jīng)寫好，不計入總詞數(shù)。

3.郵件中不得提及考生所在學校及本人姓名。

Dear Helen,

Thank you for your email. Now I would like to tell you something about

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

Best wishes!

Yours,

LiHua

查看答案和解析>>

科目：高中英語 來源：2016-2017學年廣東汕頭金山中學高二12月考試英語試卷（解析版） 題型：語法填空

Do you have any idea of New Year paintings? Also 1. (know) as "paper paintings" and "painted pictures", New Year paintings are a unique art form in Chinese folk culture. Without New Year paintings, our traditional Chinese folk culture 2. (be) much less colorful. The paintings get such a name because they are 3. (most) posted during the Chinese New Year holiday for decoration and they are also accepted 4. a symbol of New Year’s greetings.

New Year paintings 5. (appear) around the Tang dynasty, replacing the previous door pictures believed to be able to protect the residents and drive away ghosts. The New Year paintings 6. (belong) to the Song dynasty were created on a large scale. With the advancement of printing technology, the content and forms of New Year paintings became 7. (vary). The development of the paintings matured in the Ming and Qing dynasties, 8. the art hit its heyday(全盛期).

Traditional printing 9. (method) of New Year paintings include woodblock printing, stone-block printing, offset(膠印) printing, traditional Chinese painting, watercolor painting and sketches etc. Woodblock-printed New Year paintings are the most popular and interesting 10. , according to a recent survey.

查看答案和解析>>

同步練習冊答案