评价怀孕早期病毒感染与儿童出生缺陷之间的关系，最适用的研究方法是（）。 A.现况调查

螺栓连接的硬母线，其连接部分在连接前应打磨干净，并涂（）。

X线立体定向放射治疗与γ线立体定向放射治疗相比，不具有优越性的方面是（）

A.机械精度

B.病变的适应面

C.分次治疗

D.经济方面

E.灵活度

阅读理解。

     An expensive car speeding down the main street of a small town was soon caught up with by a young

motorcycle policeman. As he started to make out the ticket, the woman behind the wheel said proudly,"Before

you go any further, young man, I think you should know that the mayor of this city is a good friend of mine."

The officer did not say a word, but kept writing."I am also a friend of chief of police Barens," continued the

woman, getting more angry each moment, Still he kept on writing. "Young man," she persisted, "I know Judge

Lawson and State Senator (参议员) Patton." Handing the ticket to the woman, the officer asked pleasantly,

"Tell me, do you know Bill Bronson."

      "Why, no," she answered.

     "Well, that is the man you should have known," he said, heading back to his motorcycle,"I am Bill Bronson."

1. The policeman stopped the car because_____.

A. it was an expensive car

B. the driver was a proud lady

C. the driver was driving beyond the speed limit

D. the driver was going to make trouble for the police

2. The woman was getting more angry each moment because _____.

A. the policeman didn't know her friends

B. the policeman didn't accept her kindness

C. the policeman was going to punish her

D. she didn't know the policeman's name

3. The policeman was _______.

A. an honorable fellow

B. a stupid fellow

C. an impolite man

D. a shy man

A．信元由信元头和信元体构成，每个信元53个字节，其中信元头5个字节，信元体48个字节

B．信元由信元头和信元体构成，每个信元53个字节，其中信元头13个字节，信元体40个字节

C．信元是一个不可拆的整体

D．信元是组装起来的，每个信元48个字节

综合布线测试中，测试长度为94m是（）链路方式。

A、基本链路方式

B、通道链路方式

C、永久链路方式

D、固定链路方式