中毒型菌痢的发病因素中，可能与下列哪项有关（） A.志贺菌大量繁殖引起病情加重 B.

六十岁女性患者，因平地滑倒摔伤致左髋关节疼痛3小时就诊。查体：双下肢无畸形，髋关节无肿胀，左大粗隆轻度叩击痛。X线检查未见明显骨折脱位。

复查X线见股骨颈骨折，移位明显，应当采取的治疗手段（）

A.切开复位内固定

B.股骨头置换术

C.全髋关节置换术

D.闭合复位内固定

E.切开复位内固定加植骨术

下列河流有“地下大运河”之称的是（　　）

A．长江

B．黄河

C．坎儿井

D．塔里木河

生物群落是指生活在一定地区内的有机体包括植物、动物、微生物相互结合在一起，以多种多样的方式彼此发生作用，形成一种有规律的特殊集体。换句话说，生物群落是各种生物种群在同一特定的空间或环境范围内的自然组合，反映了该空间范围的典型自然面貌。依据上述定义，下列情形中，属于生物群落的是（）。

A．海洋中的全部鱼 

B．一个草地中的全部蛇 

C．潮湿的农贸市场上的鸡、鸭、鱼、青菜、蘑菇等 

D．一个池塘的藻类、细菌、蚌、水生昆虫等全部生物

证券公司为加强自律管理，严格要求有机会获取内幕信息的从业人员不泄漏和不利用内幕信息。 ( )

All animals must rest, but do they really sleep as we know it The answer to this question seems obvious. If an animal regularly stops its activities and stays quiet and unmoving—if it looks as though it is sleeping—then why not simply assume that it is in fact sleeping But how can observers be sure that an animal is sleeping

They can watch the animal and notice whether its eyes are open or closed, whether it is active or lying quietly, and whether it responds to light or sound. These factors are important clues, but they often are not enough. Horses and cows, for example, rarely close their eyes, and fish and snakes cannot close them. Yet this does not necessarily mean that they do not sleep. Have you ever seen a cat dozing with an eye partly open Even humans have occasionally been observed to sleep with one or both eyes partially open. Animals do not necessarily lie down to sleep either. Elephants, for example, often sleep standing up, with their tusks resting in the fork of a tree. Finally, while "sleeping" animals often seem unaware of changes in the sounds and light and other stimuli around them, that does not really prove they are sleeping either.

Observations of animal behavior alone cannot fully answer the question of whether or not animals sleep. The answers come from doing experiments in "sleep laboratories" using a machine called the electroencephalograph (EEC). The machine is connected to animals and measures their brain signals, breathing, heartbeat, and muscle activity. The measurements are different when the animals appear to be sleeping than when they appear to be awake. Using the EEC, scientists have confirmed that all birds and mammals studied in laboratories do sleep. There is some evidence that reptiles, such as snakes and turtles, do not truly sleep, although they do have periods of rest each day, in which they are quiet and unmoving. They also have discovered that some animals, like chimpanzees, cats, and moles (who live underground), are good sleepers while others, like sheep, goats, and donkeys, are poor sleepers. Interestingly, the good sleepers are nearly all hunters with resting places that are safe from their enemies. Nearly all the poor sleepers are animals hunted by other animals: they must always be watching for enemies, even when they are resting.

Animals that are good sleepers（）

A. need to have a good sleep after they have exhausted themselves by getting rid of hunting animals

B. need to have a good sleep after they get tired from hunting other animals

C. are all mammals

D. almost always have a safe resting place