问题 选择题

“艾滋病病毒(HIV)最初侵入人体时,HIV会迅速繁殖,人体免疫细胞在受到HIV攻击时也会迅速增多,并摧毁大多数HIV,但不能将其彻底消灭. HIV经过一段时间的潜伏繁殖,逐步侵袭人体的免疫系统(即人体抵抗各种外来感染的自然防卫系统),降低并最终破坏人体的免疫功能.下列表示HIV感染人体后,体液中HIV浓度和免疫细胞浓度的变化过程,其中正确的是(  )

A.

B.

C.

D.

答案

由题干可知:当HIV最初侵入人体时,HIV首先会迅速繁殖,之后,在人体免疫细胞的攻击下,大多数HIV被消灭,剩余的HIV经过一段时间的潜伏繁殖,逐步侵袭人体的免疫系统,即其在坐标中的曲线如图所示:而人体内免疫细胞的变化情况是:当HIV最初侵入人体时,人体免疫细胞在受到HIV攻击时也会迅速增多,一段时间以后,HIV逐步侵袭人体的免疫系统,降低并最终破坏人体的免疫功能,故其在坐标中的曲线变化如图所示:

故选:A

单项选择题 A1/A2型题
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     For five days, Edmonton's Downtown Park is transformed into one huge stage where artists are

able to share their talents, and where people are able to celebrate and enjoy themselves. Since its

beginning in 1980, the Edmonton Folk Music Festival has been commemorating(纪念) the true

feeling of what folk music is all about and that's the traditional togetherness(友爱) that is felt when

people gather to share stories and feelings through song.    

     This year will be the sixth year when volunteer Riedel will be offering up her time to the festival.

"People coming off a busy spring and summer have a moment of relaxation," Riedel said."It's really

easy to relax,  and it's great seeing family and friends have fun together." These families and friends

come from all different kinds of musical tastes. People who take pleasure in Blues are there, so are

people who love Bluegrass. This festival does its best to develop everyone's musical interests.    

     With so many years of experience, the festival has become a welloiled machine, and does whatever

it can to make attendees feel as comfortable as possible. There are free water stations throughout the

venue(举办地)for people to fill up their travel cups. When people buy food, reusable dishes are given

a $2 plate fee, but that is returned when the plate is brought back.      

     The festival has completely sold out of tickets,  and in record time. But with big names such as Van

Morrison and Jakob Dylan,  it's easy to see how that was going to happen. There is no parking area

during the festival, so using the Park & Ride system or Edmonton Transit is highly recommended. A

bike lockup area is provided and will be available Thursday until Sunday one hour before the gates

open until 45 minutes after the gates close.      

     The Edmonton Folk Music Festival begins on Wednesday, Aug. 4 with Van Morrison playing the

special donation fund(基金) concert,  and will finish up on Sunday, Aug. 8.

1. The Edmonton Folk Music Festival is held mainly to________.

A. gather people with different musical tastes

B. remind people of the real sense of folk music

C. exhibit the good voices of great talents in folk music

D. collect old stories of folk music

2. Which of the following is TRUE according to the passage?

A. Riedel has volunteered for the festival for at least 5 years.

B. It's hard for people to appreciate Blues.

C. It costs people a little to fill up their cups from water stations.

D. People have to pay $2 for a plate of food.

3. We can learn from the passage that________.

A. people can get tickets easily for the festival

B. the Edmonton Folk Music Festival is well organized

C. driving one's own car to the festival is highly recommended

D. bikes are available at the festival from Wednesday to Sunday

4. What would be the best title for this passage?

A. Folk Music of Blues

B. One Festival for All

C. Festival for Family Gathering

D. Edmonton's Downtown Park