A few years ago it was common to speak of a generation gap between young people and their elders. Parents said that children did not respect and listen to them, while children said that their parents did not understand them at all. What had gone wrong？ Why had the generation gap suddenly appeared？ Actually, the generation gap has been around for a long time. Many people argue that it is built into every part of our society.One important cause of the generation gap is .the opportunity that young people have to choose their own ways of life. In a more traditional society, when children grow up, they axe expected to live in the same place as their parents, to marry people that their parents know and like, and often to continue the family jobs. In our society, young people often travel great distances for their education, move out of the family at an early age, marry or live with people whom their parents have never met, and choose jobs different from those of their parents.In our society, parents often expect their children to do better than they did, to find better jobs, to make more money and to do all the things that they were unable to do. Often, that is another cause of the gap between them. Often, they discover that they have very little in common with each other.Finally, the speed at which changes take place in our society is the third cause of the gap between the generations. In a traditional culture, senior people axe valued for their knowledge, but in our society the knowledge of a lifetime may become out of date. The young and the old seem to live in two very different worlds, separated by different skills and abilities. No doubt, the generation gap will continue in American life for some time.The first paragraph tells that （）.

A.roughly

B.decidedly

C.appropriately

D.properly

Japan has taken a more independent stand _________ .

A. as it does before

B. as it did before

C. than it does a few years ago

D. than it did a few years ago

Just a few years ago， Tanya was___(home)and begging for money in front of a supermarket in New York City.

A.along with

B.in the light of

C.in

D.regardless of

A. since a few years

B. a few years before

C. for a few years

D. a few years ago

A few years ago all of them were classed ____ plants.

A: for

B: as

C: to

D: into

A.A.Right

B.B.Wrong

C.C.Not mentioned

Green Spaces in citiesWhere do children play Years ago, any open field, any vacant lot, aGreen Spaces in cities Where do children play Years ago, any open field, any vacant lot, any group pf trees--these were the places where children played. As families left family farms, small towns, and the countryside, and moved into cities, the places for their children to play in became rarer. Children in the cities had few options, fewer choices of places to play. In fact, all people’s lives change a lot when they move to the city. （）

(判断)AIDS, fifty years ago, didn’t exist.Fifteen years ago a few doctors and public health officials noticed the first cases.Within a few years it was clear that it has now killed almost 14 million people around the world.

Four years ago doctors came up with the first treatment to make a dent in the spiraling death rate.Today that treatment works for some patients, but it’s not clear how long results will last.And still there is no cure.

For the nearly 35 million people around the world now living with HIV, there may never be a cure.Once cells are infected with HIV, it is very difficult — perhaps impossible ―to rid them of the virus.The only sure way to stop AIDS is to prevent infection in the first place, and only a vaccine can do that.

Unfortunately HIV is one of the most changeable viruses known to science.After more than a dozen years, it is still rather difficult to produce effective vaccine.

Still the billions of dollars spent on AIDS research over the past 20 years has not been wasted.As scientists learn more about how HIV survives in the human body, they are realizing that drugs alone may not be enough.To contain the virus effectively, it may take a balance between drug treatments that can keep HIV levels low and a strengthened immune system that can then target and destroy the remaining virus.Until scientists find a vaccine, however, they may control but never cure the century’s final scourge.

46.AIDS didn’t exist fifteen years ago.

47.Scientists have found a vaccine which can prevent HIV infection.

48.Although some treatment works for some patients with HIV, there is still no cure.

49.HIV is a changeable virus so that it is very difficult to produce effective vaccine.

50.We have wasted billions of dollars on AIDS research.