Caffeine not only gives us a daily jump start, but new research suggests it also can strengthen long-term memory.

According to the US Food and Drug Administration, nearly 90 percent of people worldwide consume about 200 milligrams of caffeine each day. That' s equivalent to about one strong cup of coffee a day. Writing in " Nature Neuroscience" , Johns Hopkins University researchers say their findings show that caffeine strengthens certain memories for up to 24 hours after being taken in.

" We've always known that caffeine has cognitive-enhancing effects (促智效果) , but its particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans, " said senior author of the paper Michael Yassa. " We re- port for the first time a specific effect of caffeine on reducing forgetting over 24 hours. " Conducting a double-blind trial, the researchers worked with a test group of people who didn't regularly consume caffeinated products. Five minutes after studying a series of images, the test subjects were given either a placebo(無效對照劑) or a 200-milligram caffeine tablet.

To check the caffeine levels of their test subjects, the research team took saliva samples (唾液樣品) from them before they took their tablets and again one, three and 24 hours afterwards.

Both groups of test participants ( those who took the placebo and those who took the caffeine tablet) were tested the following day to see if they could recognize the images they' d seen the previous day.

The test included showing the test subjects another series of images that included some new images , those that were shown the previous day, as well as other images that were similar, but not the same as those they had viewed earlier.

The researchers found that more members of the group who were given the caffeine tablets were able to correctly identify some of the new images as " similar" to previously viewed images rather than incorrectly identifying them as the same.

"We also know that caffeine is associated with health and longevity(長壽) and may have some protective effects from cognitive decline like Alzheimer' s disease (阿爾茨海默癥). " said Yassa.

1.The purpose of the new research is ____________.

A．to examine caffeine ' s memory-strengthening effects in detail

B．to write the paper " Nature Neuroscience"

C．to prove caffeine has cognitive-enhancing effects

D．to survey how much caffeine people consume a day

2. During the research , the researchers did the following things EXCEPT ________.

A．giving the test subjects placebos or caffeine tablets

B．checking the caffeine levels of the test subjects

C．showing the test subjects series of images

D．encouraging the test subjects to drink more coffee

3. How did the test subjects show the caffeine ' s memory-strengthening effects?

A．By taking the caffeine tablets instead of placebos.

B．By recognizing images they ' d seen the previous day.

C．By identifying the new images as the same.

D．By telling the differences between new images.

4.What will the next part of the text possibly talk about?

A．Ways to achieve health and longevity.

B．The harmful effects of cognitive decline.

C．The treatment for Alzheimer' s disease.

D．The effects caffeine has on health.

練習冊系列答案
相關習題

科目：高中英語 來源：2014-2015學年遼寧師大附中高三上期中英語試卷（解析版） 題型：其他題

第三部分：詞組：(共20小題；每小題1.5分，滿分30分)

1.有消息傳來說

2.輪流

3.睡著

4.適用于……，合乎……的事實

5.是……的縮寫/簡稱

6.以……的速度

7.擺脫； 離開

8.做成某事； 取得成功

9.放好；儲存……備用

10. 理應； 應當

11.面對，正視

12.由……組成

13.做某事猶豫不決

14.簽署協(xié)議

15.擠滿

16.使某人發(fā)狂

17.建議某人做某事

18.有意義，有道理

19.屏住呼吸

20.分裂，分割

查看答案和解析>>

科目：高中英語 來源：2015-2016學年湖南兩校高二上學期期中聯(lián)考英語試卷（解析版） 題型：其他題

根據(jù)短文內容，從短文后的選項中選出能填入空白處的最佳選項，選項中有兩項為多余選項。

Planning a September trip to France

September is one of the very best months to visit France．Not only will you enjoy plenty of sunshine and warm weather, but the tourist season is beginning to wind down-which means cheaper airfares, lower prices at hotels, and fewer crowds．1.

●Go wine tasting

2. And there are plenty of wine-related events and festivals around the country．So September is a great time to visit the vineyards around the country and go wine tasting．The Bordeaux, Loire and Burgundy regions are all lovely and great places to visit vineyards．Besides that, going to the castles of the Loire region in between visiting vineyards on such warm and Sunny days is also very enjoyable．

● 3.

The temperatures are slightly lower，but plenty of sunshine makes for perfect conditions to enjoy a barge cruise on the canals of France．With such comfortable weather and beautiful scenery at this time of year, nothing equals hanging out on the deck of a barge．

●Visit the museums

Many museums in France have extended opening hours during the summer to accommodate the extra tourists and locals. And some museums also have extended opening hours into September．Wandering around the Louvre will take you into a wonder world，where you can enjoy the world-famous art． 4.

Besides the above，riding a bike through France’s villages is also a welcome activity for young visitors in September．You call shop for the most fashionable clothes or goods here．You can see the beautiful and fantastic scenery along the road． 5.

A．Take a barge cruise.

B．Enjoy the music concerts.

C．So, don’t hesitate and start to plan your September trip to France flow!

D．France is a beautiful country．

E．September is the beginning of the grape harvest season in France．

F．Going out of the Louvre, you can walk to the modern and fashionable Champs Elysees to do some shopping．

G．If this is your first trip to France, here is some handy information to help you get started planning your vacation!

查看答案和解析>>

科目：高中英語 來源：2016屆廣東百所學校高三12月質量分析聯(lián)合考試英語試卷（解析版） 題型：完形填空

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和D）中，選出可以填入空白處的最佳選項。

When I was growing up my dad would often give me small tasks to finish to help out around the house. Some were easy but the three I remember the most were the three of all. The first was helping to weed the four we had. It was work. I would rather ride my bike than crawl（爬行）in the dirt on my hands and knees the thousands of weeds in our gardens. The second was piling firewood for . It was tough work and I got more than my of pieces. I would rather walk in the woods than piling it in rows. The third was water from a mountain spring to our house. our well water had too much iron in it to .

Over the years, though, I learned to see the in all the things my dad had made me do. Having fresh vegetables for dinner was a delight. a cold glass of iced ten made from the mountain spring water was a pure . Standing by the wood stove on a snowy December day was a wonderful way to . I saw as well that all this work my dad had given me had

made me a better, stronger and more caring man. Most of all, I that when I did my work with a(n) heart, it didn’t fell like work at all.

Over the years I have learned something else too. When we do the work for our Heavenly Father with a spirit, it doesn’t feel like work, either. It feels like. Every act of kindness, word of encouragement, and gift of love we share will only make our lives better, make our hearts happier, and bring out souls to Heaven.

I am so to both my dad and my Father in Heaven. They showed me the of work and more importantly they showed me the pricelessness of love.

1.A. simplest B. toughest C. strangest D. wildest

2.A. schools B. companies C. gardens D. streets

3.A. boring B. exciting C. interesting D. relaxing

4.A. controlling B. keeping C. pushing D. pulling

5.A. festival B. winter C. holiday D. marriage

6.A. share B. charge C. point D. dream

7.A. protecting B. borrowing C. carrying D. conducing

8.A. because B. unless C. although D. but

9.A. boil B. match C. get D. drink

10.A. requirements B. attention C. rewards D. experience

11.A. Designing B. Enjoying C. Performing D. Developing

12.A. desire B. challenge C. surprise D. pleasure

13.A. turn up B. warm up C. stay up D. set up

14.A. unluckily B. immediately C. gradually D. temporarily

15.A. remembered B. ignored C. regretted D. realized

16.A. honest B. happy C. brave D. modest

17.A. loving B. complaining C. hating D. punishing

18.A. closer B. farther C. politer D. warmer

19.A. kind B. lucky C. grateful D. vital

20.A. key B. way C. goal D. value

查看答案和解析>>

科目：高中英語 來源：2015-2016學年吉林長春市高一上學期第三次月考英語試卷（解析版） 題型：單項填空

---Don’t worry, Jim. I can lend you the money.

---Thank you very much, Bob. You are always so __________.

A. mean B. generous C. peaceful D. active

查看答案和解析>>

科目：高中英語 來源：2015-2016學年吉林長春第二中學高二上第三次月考英語試卷（解析版） 題型：閱讀理解

Five years ago, David Smith wore an expensive suit to work every day. “I was a clothes addict,” he jokes. “I used to carry a fresh suit to work with me so I could change if my clothes got wrinkled.” Today David wears casual clothes-khaki pants and sports shirt to the office. He hardly ever wears a necktie. “I’m working harder than ever,” David says, “and I need to feel comfortable.”

More and more companies are allowing their office workers to wear casual clothes to work in the United States. The change from formal to casual office wear has been gradual. In the early 1990s, many companies allowed their employees to wear casual clothes on Friday(but only on Friday). This became known as “dress-down Friday” or “casual Friday”. “What started out as an extra one-day-a-week benefit for employees has really become an everyday thing.” said business consultant Maisly Jones.

Why have so many companies started allowing their employees to wear casual clothes? One reason is that it’s easier for a company to attract new employees if it has a casual dress code. “A lot of young people don’t want to dress up for work,” says the owner of a software company, “so it’s hard to hire people if you have a conservative dress code.” Another reason is that people seem happier and more productive when they are wearing comfortable clothes. In a study conducted by Levi Strauss and Company, 85 percent of employers said that they believe that casual dress improves employee morale(士氣). Only 4 percent of employers said that casual dress has a negative impact on productivity. Supporters of casual office wear also argue that a casual dress code helps them save money. “Suits are expensive, if you have to wear one every day,” one person said. “For the same amount of money, you can buy a lot more casual clothes.”

1.David Smith refers to himself as having been “a clothes addict,” because _______.

A. he often wore khaki pants and a sports shirt

B. he couldn’t stand a clean appearance

C. he wanted his clothes to look neat all the time

D. he didn’t want to spend much money on clothes

2.David Smith wears casual clothes now, because _______.

A. they make him feel at ease when working

B. he cannot afford to buy expensive clothes

C. he looks handsome in casual clothes

D. he no longer works for any company

3.According to this passage, which of the following statements is false?

A. Many employees don’t like a conservative dress code.

B. Comfortable clothes make employees more productive.

C. A casual clothes code is welcomed by young employees.

D. All the employers in the U. S. are for casual office wear.

4.In this passage, the following advantages of casual office wear are mentioned in the passage except _______.

A. saving employees’ money

B. making employees more attractive

C. improving employees’ motivation

D. making employees happier

查看答案和解析>>

科目：高中英語 來源：2016屆江西省南昌市高三上學期第三次考試英語試卷（解析版） 題型：閱讀理解

A man once said how useless it was to put advertisements in the newspapers. “l(fā)ast week,” said he, “my umbrella was stolen from a London church. As it was a present, I spent twice its worth in advertising, but didn't get it back. ”

“How did you write your advertisement?” asked one of the listeners, a merchant.

“Here it is, said the man, taking out of his pocket a slip cut from a newspaper.

The other man took it and read, “Lost from the City Church last Sunday evening, a black silk umbrella. The gentleman who finds it will receive ten shillings on leaving it at No. 10 Broad Street. ”

“Now, “Said the merchant, “I often advertise, and find that it pays me well. But the way in which an advertisement is expressed is of extreme importance. Let us try for your umbrella again, and if it fails, I'll buy you a new one. ”

The merchant then took a slip of paper out of his pocket and wrote: “If the man who was seen to take an umbrella from the City Church last Sunday evening doesn't wish to get into trouble, he will return the umbrella to No. 10 Broad Street. He is well known. ”

This appeared in the paper, and on the following morning, the man was astonished when he opened the front door. In the doorway lay at least twelve umbrellas of all sizes and colours that had been thrown, and his own was among them. Many of them had notes fastened to them saying that they had been taken by mistake, and begging the loser not to say anything about the matter.

1.The result of the first advertisement was that ______________.

A． the umbrella was found somewhere near the church

B． the man got his umbrella back

C． nobody found the missing umbrella

D． the man wasted some money advertising

2.The merchant suggested that the man should _______________.

A． buy a new umbrella

B． report the police

C． go on looking for his umbrella

D． write another and better advertisement

3.“If it fails, I’ll buy you a new one,” suggested that the merchant ______________.

A． wanted to buy him a new umbrella

B． didn’t know what to do

C． was rich enough to buy one

D． was quite sure of success

4.The story is mainly about _________________.

A． a useless advertisement

B． how to make an effective advertisement

C． what the merchant did for the umbrella owner

D． how the man lost and found his umbrella

查看答案和解析>>

科目：高中英語 來源：2016屆遼寧省大連市高三12月月考英語試卷（解析版） 題型：短文改錯

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。錯誤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。

On a snowy winter night, a bus with 45 passenger had an accident because the wet road. And all of them were trapping in the bus and what is worse, the bus ran out of gas and it was very cold in it. They could do nothing but to wait for help. A man who lived nearby saw that had happened. He and some villagers succeeded in open the door and helped all of them out of the bus. He took them to his home but offered food and water and even some warm clothes to the children. They spent two days in their home and finally help came. All of them were thankfully for their help.

查看答案和解析>>

科目：高中英語 來源：2016屆廣東東莞市六校高三上學期聯(lián)考英語試卷（解析版） 題型：短文改錯

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, my foreign teacher Tim and I went to the People’s park together. We take a taxi and it wasn’t long before we arrived at the park. On seeing the green trees and beautiful flower, Tim couldn’t wait for to take pictures. It was at that moment when we found his camera was missing. He was very worried but searched all over his backpack. Sadly, he just couldn’t find it. Suddenly it struck me that he might have left it in the taxi. So I immediately got touch with the taxi company. About half an hour later, the driver returned a camera. Both of us were gratefully to the driver, and Tim, in particular, insisted on have a photo taken with him. Tim and I enjoyed themselves during the rest of the day.

查看答案和解析>>

同步練習冊答案