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类比是一种有效的学习方法，通过归类和比较，有助于掌握新知识，提高学习效率．在类比过程中，既要找出共同之处，又要抓住不同之处．某同学对机械波和电磁波进行类比，总结出下列内容，其中不正确的是（　　）

A．机械波的频率、波长和波速三者满足的关系，对电磁波也适用

B．机械波和电磁波都能产生干涉和衍射现象

C．机械波的传播依赖于介质，而电磁波可以在真空中传播

D．机械波既有横波又有纵波，而电磁波只有纵波

屡孕屡堕，孕后腰膝酸软，头晕耳鸣，夜尿频多，面色晦暗，舌质淡，苔薄白，脉细滑尺脉沉弱。治疗首选方（）

A.肾气丸

B.六味地黄丸

C.补肾固冲汤

D.育阴汤

E.泰山磐石散

Scientists from the Max Plank Institute for Biological Cybernetics in Tubingen, Germany, have presented the first experimental evidence that people do end up walking in circles if lost in unfamiliar areas．The study, published in the journal Current Biology, examined the tracks of people who walked for several hours in the Sahara desert in Tunisia and in the Bienwald forest in Germany．Researchers Jan Souman and Marc Ernst said the scientists used the global positioning system （GPS） to record these paths．The results showed that the walkers were only able to keep a straight line when the sun or moon was visible．As soon as the sun disappeared behind some clouds, people started to walk in circles without even noticing it．

Souman said one explanation offered in the past for people walking in circles was that most people have one leg longer or stronger than the other, which would produce a systematic bias（偏差） in one direction．To test this．the researchers asked people to walk straight while blindfolded which removed the effects of vision．They found that these circles were rarely in a systematic direction, with the same person sometimes switching to the left and sometimes to the right．

"Most of the participants in the study walked in circles, sometimes in extremely small ones．Walking in circles is therefore not caused by differences in leg length or strength, but more likely the result of increasing uncertainty about where straight ahead is," said Souman, "Small random errors （随机性误差） in the various sensory signals that provide information about walking direction add up over time, making what a person perceives to be straight ahead drift away from the true straight ahead direction．"

72．The underlined word "this" in Paragraph 2 refers to _____．

A．the effects of vision             B．a systematic bias

C．the leg length differences         D．one explanation offered in the past

73．What is the probable reason for people's walking in circles?

A．The invisible sun or moon．

B．The increasing uncertainty about directions．

C．Differences in leg length or strength．

D．Wrong signals providing information about areas．

74．Why are the subjects required to be blindfolded?

A．To encourage them to walk straight．    B．To stop them from seeing each other．

C．To dismiss the effects of vision． D．To keep the test a top secret．

75．Which of the following statements is true?

A．People walk straight in the day．

B．The farther people walk, the greater the direction bias grows．

C．People walk only in large circles．

D．Researchers use the global positioning system to record their tracks．

癫痫、肾功能不全、机械性肠梗阻、心绞痛患者禁甩（）。

A.石杉碱甲

B.多奈哌齐

C.奥拉西坦

D.利斯的明

E.吡拉西坦

屏障系统是清洁级、SPF级动物生产或实验的设施。要求水、垫料、空气及其它物品均需进行严格的微生物控制。设施内送入的空气需经初、中、高效三级过滤，换气次数为10-20次，洁净度达到（），相对湿度为40-70%，温度为20-250C。

A．100级

B．1000级

C．5000级

D．10000级