The scientists observed that the more junk food the rats ate, the more they wanted to eat – a behavior very similar to that of rats addicted(上了癮的) to heroin, a dangerous drug. Johnson said the experiment shows that the brain chemistry of obesity(肥胖) and drug addiction may be quite similar.

In their experiment, Johnson and his team studied the “pleasure center” of rats’ brains. The pleasure center is a complicated network of nerve cells. If the animal exercises or eats, the cells reward the animal by releasing chemicals into the body that make it feel good. And when the body feels good, the animal – or person – will want to do the behavior again.

For the experiment, Johnson fed foods like cheesecake to one group of rats. Food like this is high in calories and fat. Another group of rats got a regular diet. The rats that ate junk food started to eat more and more.

“They’re taking in twice the amount of calories as the control rats,” says Paul Kenny, one of Johnson’s colleagues.

Kenny and Johnson wanted to know what was going on in the brains of these rats. They first designed a way to deliver a small electrical charge to the rats’ brains. This electrical charge would stimulate the pleasure centers to release pleasure-causing chemicals. The rats could control how much stimulation – and how much pleasure – they received by running on a wheel. The more the rat ran, the more pleasure it received.

The rats that had been eating junk food started running more and more. This behavior suggested that the junk-food-eating rats needed more brain stimulation to feel good compared with rats on a normal diet. In other words, their pleasure centers were becoming less sensitive and the junk food didn’t make them feel good unless they ate more and more.

Experiments like this one could help scientists understand how chemicals in the brain contribute to obesity. With that information, they may be able to help people avoid obesity in the first place.

(Note: Answer the questions or complete the statements in NO MORE THAN TEN WORDS.)

1.The scientists suggested it was actually ___________________ that made the rats feel good.

2.How did the scientist know what was happening in the brains of the junk-food-eating rats?

3.What was the purpose of the experiment mentioned in the article?

Fill in the blanks with the proper forms of given words. (7’)

1.A double room with a balcony overlooking the sea had been __________ (reservation) for him.

2.Our new offices are still under ___________ (construct), and this is not my office.

3.Nov.11 is __________ (reference) to as “Singles’ Day” by netizens nationwide.

4.They launched a campaign to save wild pandas from __________ (extinct).

5.Her ___________ (decide) to live abroad was a terrible blow to her parents.

6.The directors of the company refused to undertake such a ___________ (risk) venture.

7.Children are not usually allowed in, but I’m prepared to make an __________ (except) in this case.

Directions: Translate the following sentences into English. You are required to use the word given in the bracket for each respective sentence.

1.他的成功與他的勤奮有密切關(guān)系。（relate）

2.那個有嚴(yán)重心臟病的老人明天將要動手術(shù)。(operate)

3.這個藝術(shù)家不得不在很小的時候自己照顧自己。（take care of）

4.任何事情如果要把它做好的話都需要大量的時間和精力。(involve)

5.老師堅持學(xué)生每日應(yīng)有至少8個小時的睡眠。（insist）

George couldn't remember when he first met Mr.Anderson, but he was sure it was___Sunday s___ because everybody was at__church.

A./; the B.the; /

C.a; / D./; a

【考點】冠詞

Surprisingly, years back, when playing American Captain in Marvel’s movie universe became ______ possibility, Chris Evans nearly turned ______ role down.

A. the; a B. the; the

C. a; the D. /; the

It is quite warm _________January in Chongqing.

A. to B. with

C. in D. for

—What do you think of teaching?

—I find it fun and demanding. It is a job____ you are doing something serious

but interesting.

A. where B. which C. that D. what

—Linda, I have to stay at school and take some courses next month, how about you?

—I ____ to Canada at this time next month since I have got the visa.

A. will be flying B. will fly

C. have been flying D. have flown

I am decorating my office now. I _______ comfortably in my office at this time tomorrow.

A. am sitting B. was sitting

C. sit D. will be sitting

—Shall we have a smoke here?

—No, we _____ because this is gas station and the worker is carrying some petrol.

A. can’t B. needn’t

C. mustn’t D. won’t