病原体在吸血节肢动物体内增殖或完成其生活周期中某阶段后才具有传染性，所需的这段时间称

已知X与Y的相关系数r₁=0.38，在0.05的水平上显著；A与B的相关系数r₂=0.18，在0.05的水平上不显著。则( )

A．r₁与r₂在0.05的水平上差异显著

B．T₁与r₂在统计上肯定有显著差异

C．无法推知r₁与r₂在统计上差异是否显著

D．r₁与r₂在统计上并不存在显著差异

What is great art? On the one hand, we can all see that great art is old art which is called great. But how do we know which art of our own times is great, and which will be forgotten? And who decides?

These are important questions, for the great art of the past often was not considered great during its own time. When Shakespeare and Charles Dickens were writing, for example, most critics considered them as hack (平庸的) writers with little or no literary ability.

Similarly, Van Gogh and many of the other Impressionist painters of the late nineteenth century were not allowed to participate in events involving what were thought to be the "real" painters of the time, and often they were very poor. Yet today their paintings often sell for millions of dollars, while those so-called "real" painters are now barely remembered.

So what makes great art? Can, for example, rock music be great art? Music videos? Cartoons and comics? Those who call themselves critics of the fine arts often have been the last to recognize great art in the past, and we can probably expect this to be the situation today.

Critics often don’t recognize great art because they tend to be prejudiced against what is popular. Popular works, whether they are novels, movies, or comics, are usually considered to be produced for the sake of money only, and not for the sake of art.

But popularity, it seems to me, is one of the three signs that a present-day work of art may come to be thought of as great. The other two are that it is groundbreaking, and that it is inherently (内在的) beautiful.

Many works have one or even two of these qualities of being popular, unusual, and beautiful. But having all the three often will mean that a work of art will someday be seen to be great, though it may take a good spoonful of time, such as a century or two, to know for sure.

小题1:The first paragraph is intended to__________.

A．lead to the following and arouse the reader’s curiosity

B．introduce some real painters to the readers

C．introduce the questions the writer wants to answer

D．explain what kind of art will become popular小题2:The author used the examples of Shakespeare, Charles Dickens and Van Gogh to prove _____.

A．these masters’ works have some shortcomings

B．these masters wouldn’t have been so successful without the critics

C．truly beautiful works of art are never understood when first created

D．great masters are often not acknowledged while they were alive小题3:According to the author, great works _______.

A．may be presented in different forms

B．are generally valued by critics

C．are thought valuable because of their sale price

D．will lose their value if they’re not accepted小题4:What can be inferred from the passage?

A．Critics have changed their attitudes to great works.

B．Most of the opinions of critics are valueless.

C．The work of art itself, not the critics, determines its greatness.

D．Works of Impressionist painters will be great one day.

甲状旁腺素的分泌与以下哪项有关（）。

A.甲状腺控制

B.血磷浓度

C.垂体控制

D.血钙浓度

E.下丘脑控制

Robert Moody, 52, is an experienced police officer. Much of his work involves dealing with (16) and gang (团伙)problems in the schools of his community. Knowing that many kids often (17) trouble, he decided to do something about it. So in 1991 he began to invite small groups of kids to go fishing with him on his day (18) .

Those fun trips had a(n) (19) impact. A chance encounter in 2000 proved that. One day, (20) working security at a school basketball game, Moody noticed two young guys (21) . He sensed trouble between them. (22) one of them headed toward Moody and gave him a hug. "I (23) you. You took me (24) when I was in fifth grade. That was one of the (25) days of my life. "

Deeply touched by the boy’ s word, Moody decided to create a foundation (基金会)that (26) teenagers to the basics of fishing in camping programs. "As a policeman, I saw (27) there was violence, drugs were always behind it. They have a damaging (28) on the kids," says Moody.

By turning kids on to fishing, he (29) to present an alternative way of life, "When you’ re sitting there waiting for a (30) ," he says, "you can’t help but talk to each other, and such (31) can be pretty deep. "

"Talking about drugs helped prepare me for the peer(同龄人)pressures in high school," says Michelle, 17, who (32) the first program. "And I was able to help my little brother (33) drugs. "

Moody faces (34) in three years, when he hopes to run the foundation full-time. "I’ m living a happy life and I have a responsibility to my (35) to give back," Moody says. "If I teach a kid to

fish today, he can teach his brother to fish tomorrow. \

27().

A. where

B. unless

C. as

D. whether

电容器向外释放电荷时就叫（）。