与股票投资相比，债券投资的优点有( )。 A．本金安全性好 B．投资收益率高 C．

男，39岁，眼睑及双下肢水肿20天，尿常规蛋白阳性，血浆白蛋白22g／L，血肌酐72μmol／L最可能的诊断是（）

A.肝硬化

B.流行性出血热肾损害

C.急性肾小球肾炎

D.急进性肾小球肾炎

E.肾病综合征

疑“胆总管结石”，应首选（）

A.口服胆囊造影

B.ERCP

C.低张十二指肠造影

D.肠系膜上动脉造影

E.腹部平片

我国成功发射了自行研制的“神舟七号”宇宙飞船，首次进行了宇航员的太空行走，飞船顺利返回地面，这是我国航天事业的一个新的里程碑．当飞船在环绕地球的轨道上飞行时，所需的向心力由地球对它的______提供；此时飞船中的航天员处于______（选填“超重”或“失重”）状态．

Suppose we built a robot to explore the planet Mars. We provide the robot with seeing detectors to keep it away from danger. It is powered entirely by the sun. Should we program the robot to be equally active at all times No, the robot would be using up energy at a time when it was not receiving any. So we would probably program it to stop its activity at night and to wake up at dawn the next morning.
According to evolutionary theory of sleep, evolution equipped us with a regular pattern of sleeping and waking for the same reason. The theory does not deny that sleep provides some important restorative functions. It merely says that evolution has programmed us to perform those functions at a time when activity would be inefficient and possibly dangerous. However, sleep protects us only from the sort of trouble we might walk into; it does not protect us from trouble that comes looking for us. So we sleep well when we are in a familiar, safe place, but we sleep lightly, if at all, when we fear that bears will nose into the tent.
The evolutionary theory explain the differences in sleep among creatures. Why do cats, for instance, sleep so much, while horses sleep so little Surely cats do not need five times as much repair and restoration as horses do. But cats can afford to have long periods of inactivity because they spend little time eating and are unlikely to be attacked while they sleep. Horses must spend almost all their waking hours eating, because what they eat is very low in energy value. Moreover, they cannot afford to sleep too long or too deeply, because their survival depends on their ability to run away from attackers.

Which of the following is the main idea of the passage

A. Evolution has equipped all creatures with a regular pattern of sleeping and waking.
B. The study of sleep is an important art of the evolutionary theory.
C. Sleeping patterns must be taken into consideration in the designing of robots.
D. The sleeping pattern of a living creature is determined by the food it eats.

急性胆囊炎表现有右肩背部疼痛，这种疼痛属于（）

A.内脏性疼痛

B.躯体性疼痛

C.牵涉性疼痛

D.转移性疼痛

E.胆绞痛