变换投影面求线段实长的方法，关键就是做辅助投影面并使其与所求直线（），然后再将辅助投

男性，48岁，心脏超声检查示心脏周围液性暗区环绕，左心室后壁液暗区厚约2.8cm，右心室前壁出现塌陷征，心脏呈摇摆征，诊断心包积液为（）。

A.微量

B.少量

C.中量

D.大量

E.以上都不正确

关于细胞毒性脑水肿描述，错误的是（）

A、多由脑缺血缺氧引起 

B、常见于超急性脑梗死或急性、亚急性脑梗死病灶的周围 

C、脑组织缺血初期以细胞毒性水肿为主，随后出现血管源性水肿 

D、T1WI信号变化不如T2WI敏感 

E、DWI技术是目前检出细胞毒性脑水肿最敏感的方法，呈现高信号，ADC值明显升高 

阅读理解。

     The way people hold to the belief that a fun-filled, pain free life equals happiness actually reduces their

chances of ever attaining real happiness. If fun and pleasure are equal to happiness then pain must be equal to

unhappiness. But in fact, the opposite is true: more often than not things that lead to happiness involve some

pain.

     As a result, many people avoid the very attempts that are the source of true happiness. They fear the pain

inevitably (不可避免的) brought by such things as marriage, raising children, professional achievement,

religious commitment (义务), self-improvement.

     Ask a bachelor (单身汉) why he resists marriage even though he finds dating to be less and less satisfying.

If he is honest he will tell you that he is afraid of making a commitment. For commitment is in fact quite painful. The single life is filled with fun, adventure, excitement. Marriage has such moments, but they are not its most

distinguishing features.

     Couples with infant children are lucky to get a whole night's sleep or a three-day vacation. I don't know

any parent who would choose the word fun to describe raising children. But couples who decide not to have

children never know the joys of watching a child grow up or of playing with a grandchild.

     Understanding and accepting that true happiness has nothing to do with fun is one of the most liberating

realizations. It liberates (解放)  time: now we can devote more hours to activities that can genuinely increase

our happiness. It liberates money: buying that new car or those fancy clothes that will do nothing to increase

our happiness now seems pointless. And it liberates us from envy: we now understand that all those who are

always having so much fun actually may not be happy at all..

1. According to the author, a bachelor resists marriage chiefly because _______.

A. he finds more fun in dating than in marriage

B. he believes that life will be more cheerful if he remains single

C. he is reluctant to take on family responsibilities

D. he fears it will put an end to all his fun adventure and excitement

2. Raising children, in the author's opinion is _______.

A. a rewarding task

B. a thankless job

C. a moral duty

D. a source of inevitable pain

3. From the last paragraph, we learn that envy sometimes stems from(由…造成)_______.

A. hatred　　

B. ignorance

C. prejudice(偏见)　　　

D. misunderstanding

4. To understand what true happiness is one must ________.

A. have as much fun as possible during one's lifetime

B. be able to distinguish happiness from fun

C. put up with pain under all circumstances

D. make every effort to liberate oneself from pain

5. What is the author trying to tell us?

A. It is important to make commitments.

B. One must know how to attain happiness.

C. Happiness often goes hand in hand with pain.

D. It is pain that leads to happiness.

某行政机关和受另一个行政机关委托行使权力的组织在行使职权过程中共同侵犯了某公民的合法权益并造成损害，在这个案件中，赔偿义务机关应当是__________。

A．某行政机关

B．某行政机关和另一行政机关

C．某行政机关和另一行政机关委托的组织

D．受另一个行政机关委托的组织

试述冲任损伤和月经病的关系