导致X线照片模糊的因素，哪项不是A．X线管焦点的大小 B．被检体的运动 C．屏胶组合

颈椎的特有结构是

A．椎体
B．椎板
C．横突孔
D．上关节突
E．下关节突

阅读理解。

     Five years ago, David Smith wore an expensive suit to work every day. "I was a clothes addict (有瘾的

人)" he jokes."I used to carry a fresh suit to work with me so I could change if my clothes got wrinkled (皱的)." Today David wears casual clothes-khaki pants and a sports shirt-to the office. He hardly ever wears a

necktie. "I am working harder than ever," David says, "and I need to feel comfortable." More and more

companies are allowing their office workers to wear casual clothes. In the United States, the change from

formal to casual office wear has been gradual. In the early 1990s, many companies allowed their employees

to wear casual clothes on Friday (but only on Friday). This became known as "dress-down Friday" or "casual

Friday"."What started out as an extra one-day-a-week benefit for employees has really become an everyday

thing," said a business consultant (顾问) Maisly Jones.

     Why have so many companies started allowing their employees to wear casual clothes? One reason is

that it's easier for a company to attract new employees if it has a casual dress code.""A lot of young people

don't want to dress up for work," says the owner of a software company, "so it's hard to hire people if you

have a conservative (保守的) dress code." Another reason is that people seem happier and more productive

when they are wearing comfortable clothes. In a study conducted by Levi Strauss Company, 85 percent of

employers believe that casual dress has a negative influence on morale (士气). Only 4 percent of employers

hold the opinion that casual dress has a negative influence on productivity. Supporters of casual office wear

also argue that a casual dress code helps them save money. "Suits are expensive, if you have to wear one

every day," one person said. "For the same amount of money, you can buy a lot more casual clothes."

1. David Smith refers to himself as having been"a clothes addict," in the first paragraph because ________.

A. he often wore khaki pants and a sports shirt

B. he couldn't stand a clean appearance

C. he wanted his clothes to look neat all the time

D. he didn't want to spend much money on clothes

2. David Smith wears casual clothes now, because ________.

A. they make him feel at ease when working

B. he cannot afford to buy expensive clothes

C. he looks handsome in casual clothes

D. he no longer works for any company

3. According to this passage, which of the following statements is FALSE?

A. Many employees don't like a conservative dress code.

B. Comfortable clothes make employees more productive.

C. A casual clothes code is welcomed by young employees.

D. All the employers in the U.S. support casual office wear.

4. According to this passage, which of the following statements is TRUE?

A. Company workers started to dress down about twenty years ago.

B. Dress-down has become an everyday phenomenon (现象) since the early 1990s.

C. "Dress-down Friday" was first given as a favor from employers.

D. Many workers want to wear casual clothes to attract people.

5. In this passage, the following strong points of casual office wear are mentioned EXCEPT ________.

A. saving employees' money

B. making employees more attractive

C. improving employees' motivation (动机)

D. making employees happier

下列物质中加入金属钠不产生氢气的是[ ]

A．乙醇

B．乙酸

C．水　

D．苯

在线摄影中，将滤线栅置于胶片与肢体之间，焦点到滤线栅的距离与滤线栅焦距相等，并使X线中心线对准滤线栅中心线。使用滤线栅摄影时，冲洗后的照片有的中心有密度而两侧无密度，有的一边高密度，一边低密度。

射线因素（线质、线量、散射线）对影像信息的影响正确的是（）

A.线质越硬，穿透能力越小

B.线量对影像密度无影响

C.散射线导致照片对比度降低

D.射线量越多，照片密度越小

E.散射线是成像的有用信息

著作权保护的是（），《计算机软件保护条例》规定非职务软件的著作权归（）

著作权保护的是（）

A．作品的思想内容

B．作品的表达形式

C．作品的手稿

D．作品的名称