On June 5, 1981 the Centers for Disease

问题：

On June 5, 1981 the Centers for Disease Control in Atlanta, U.S. announced the presence of a rare, infectious disease in five American homosexuals(同性恋). Soon doctors were finding similar cases all over the country and the world. The AIDS epidemic(流行病)had officially begun. By 1983 it was clear that AIDS had spread around the world. More than twenty years later, AIDS has left twenty-six million dead and another forty million infected.  AIDS has become the worst medical disaster ever experienced by mankind.

Hundreds of young people between the ages of 20 and 45 died each week during the early years of the U.S. AIDS. More than 600,000 cases of AIDS have been reported since 1981 in the United States, and it is estimated that there may be as many as 900,000 Americans infected with HIV.

Though the rate of HIV infections continues to increase in the United States, the number of AIDS cases has fallen sharply since 1996, when antiretroviral drugs came onto the market. Unfortunately, the AIDS epidemic continues today in Africa and much of Asia, where antiretroviral treatment is not available and health care is far from enough. AIDS is the fourth leading cause of death worldwide, and the No. 1 cause of death due to infectious disease.

HIV, the virus that causes AIDS, was first separated in 1983 by a team at the Pasteur Institute in Paris. That discovery made it possible to develop a test for AIDS and trace back to victims who may have died before doctors were aware of the disease.

However, scientists still don't know exactly how and where AIDS started. Finding the source of AIDS could be important in developing a vaccine(疫苗) and be important in mapping the future course of the epidemic.

小题1:It can be inferred from the passage that       

A．antiretroviral drugs will be obtained easily all over the world

B．the best way to stop AIDS is to develop a vaccine

B．scientists will soon find a way to cure AIDS

D．there will be fewer AIDS cases in the world in the future

小题2:Which areas are the most worrying places where AIDS spreads quickly? 

A．Africa.

B．Asia.

C．The United States.

D．France.小题3:The number of AIDS cases has greatly decreased in the United States due to the fact

A．a team at the Pasteur Institute in Paris succeeded in separating HIV

B．some effective medicine has been invented

B．scientists understand AIDS better and better.

D．The rate of HIV infections continue to rise in the United States

小题4:What's the importance of the discovery of the source of AIDS?

A．It can be used to develop a test for AIDS.

B．It can stop HIV forming AIDS.

B．It can reduce the rate of death caused by AIDS.

D．It can help develop a drug to prevent AIDS.