一般地讲，随着研究中的样本含量增加，下列哪一个指标会相应地减小（）。 A.偏倚 B.

经皮椎间盘切吸术并发症中，例外的是（）

A.截瘫

B.出血形成腰肌血肿

C.腰椎间盘感染

D.神经损伤

E.穿入腹腔引起脏器损伤

（1）作出图1经空气斜射入玻璃的折射光线．

（2）根据图2中经透镜折射后的光线画出入射光线．

（3）如图3所示，这是一个近视眼观察远处物体的未完成的光路图，请在图中将光路补充完整．

阅读理解。

     On a cold January morning in a Washington, DC Metro Station, a man with a violin played for about an

hour. During that time approximately 2,000 people went through the station, most of them on their way to

work.

     After 3 minutes a middle-aged man noticed there was a musician playing. He stopped for a few seconds

and then hurried on. Four minutes later the violinist received his first dollar: a woman threw the money in

the hat without stopping and continued to walk. After 6 minutes, a young man leaned against the wall to

listen to him, then looked at his watch and walked away. After 10 minutes, a 3-year-old boy stopped but his

mother dragged him along hurriedly. This action was repeated by several other children. Every parent,

without exception, forced their children to move on quickly.

     Finally only 6 people stopped and listened for a short while. About 20 gave money, but continued to walk

at their normal pace. The man collected a total of $ 32. When he finished playing, no one applauded.

     The violinist was Joshua Bell, one of the greatest musicians in the world. He played one of the most

intricate(复杂的) pieces ever written, with a violin worth $ 3.5 million dollars. Two days before, Joshua Bell

sold out a theatre in Boston where the seats averaged $ 100 each.

     The program was organized by the Washington Post as part of a social experiment about perception, taste,

and people's priorities. In a common place environment, at an inappropriate hour, do we perceive beauty? Do

we stop to appreciate it? Do we recognize talent in an unexpected context?

     If we do not take a moment to stop and listen to one of the best musicians in the world, playing some of

the finest music ever written, how many other things are we missing?

1. The first paragraph intends to tell us _____.

A. the man chose a bad place for playing

B. few people showed interest in music

C. how busy people were that morning

D. what background the story was set in

2. Compared to their parents, the children seemed to _____.

A. have more spare time

B. be more easily touched by music

C. be better at playing the violin

D. have more music knowledge

3. We call infer from the passage that _____.

A. none of the passers-by were fond of music

B. beauty can only be enjoyed in particular places

C. Joshua Bell first played the violin in the station

D. in a way, the violinist was mistaken as a beggar

4. According to the writer, people should _____.

A. listen to as many great musicians as possible

B. try to create beautiful things for others to enjoy

C. show kindness to anyone whether they're rich or not

D. notice and appreciate what's going on in their daily life

担保人可按下列方式对被担保人及反担保人进行债务追索（）

A.扣付定金

B.直接向被担保人追索债务

C.向担保人追索债务

D.向反担保人追索债务

入芝兰之室，久而不闻其香，说的是嗅觉的（）。

A.适应

B.代偿

C.对比

D.联觉