正常的下肢负重力线由下述哪3点连成的直线构成()。 A.髂前上棘、髌骨中点、内踝下缘

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问题:

正常的下肢负重力线由下述哪3点连成的直线构成()。

A.髂前上棘、髌骨中点、内踝下缘

B.髂前上棘、髌骨中点、第一趾蹼

C.股骨大转子、髌骨中点、内踝下缘

D.股骨大转子、髌骨中点、第一趾蹼

E.髂前上棘、髌骨中点、踝关节中点

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圆周长的计算公式C=2πr,其中的C和r成反比例关系.______.

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从宇宙中看地球,地球是一个蔚蓝色的十分美丽的球体,原因是[ ]

A.地球表面完全是海洋

B.地球上七分海洋,三分陆地

C.地球被云层所包围

D.地球被水汽包围

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如图所示,O1为皮带的主动轮的轴心,轮半径为r1,O2为从动轮的轴心,轮半径为r2,r3为固定在从动轮上的小轮半径。已知r2=2r1,r3="1.5r1" .A、B和C分别是3个轮边缘上的点,质点A、B、C的向心加速度之比是

A.1:2:3     B.8:4:3    C.3:6:2        D.2:4:3

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Someday a stranger will read your e-mail without your permission or scan the Website you’ve visited,Or perhaps someone will casually glance through your credit card purchases or cell phone bills to find out your shopping preferences or calling habits.

In fact, it’s likely some of these things have already happened to you. Who would watch you without your permission? It might be a spouse, a girl friend, a marketing company, a boss, a cop or a criminal. Whoever it is, they will see you in a way you never intended to be seen --- the 21st century equivalent of being caught naked.

Psychologists tell us boundaries are healthy, that it's important to reveal yourself to friends, family and lovers in stages, at appropriate times.But few boundaries remain. The digital bread crumbs (碎屑) you leave everywhere make it easy for strangers to reconstruct who you are, where you are and what you like. In some cases, a simple Google search can reveal what you think. Like it or not, increasingly we live in a world where you simply cannot keep a secret.

The key question is: Does that matter?

For many Americans, the answer apparently is “no.”

When opinion polls ask Americans about privacy, most say they are concerned about losing it. A survey found an overwhelming pessimism about privacy, with 60 percent of respondents saying they feel their privacy is “slipping away, and that bothers me.”

But people say one thing and do another. Only a tiny fraction of Americans change any behaviors in an effort to preserve their privacy. Few people turn down a discount at tollbooths (收费站) to avoid using the EZ-Pass system that can track automobile movements. And few turn down supermarket loyalty cards. Privacy economist Alessandro Acauisti has run a series of tests that reveal people will surrender personal information like Social Security numbers just to get their hands on a pitiful 50-cents-off coupon (优惠卷).

But privacy does matter - at least sometimes. It’s like health: When you have it, you don’t notice it. Only when it’s gone do you wish you’d done more to protect it.

小题1:What does the author mean by saying “the 21st century equivalent of being caught naked” (Lines 3-4, Para. 2)?

A.People's personal information is easily accessed without their knowledge.

B.In the 21st century people try every means to look into others’ secrets.

C.People tend to be more frank with each other in the information age.

D.Criminals are easily caught on the spot with advanced technology.小题2:What would psychologists advise on the relationships between friends?

A.Friends should open their hearts to each other.

B.Friends should always be faithful to each other.

C.There should be a distance even between friends.

D.There should be fewer disputes between friends.小题3:Why does the author say “we live in a world where you simply cannot keep a secret” ( Line5,  para. 3)?

A.Modern society has finally evolved into an open society.

B.People leave traces around when using modern technology.

C.There are always people who are curious about others’ affairs.

D.Many search engines profit by revealing people’s identities.小题4:What do most Americans do with regard to privacy protection?

A.They change behaviors that might disclose their identity.

B.They use various loyalty cards for business transactions.

C.They rely most and more on electronic devices.

D.They talk a lot but hardly do anything about it.小题5:According to the passage, privacy is like health in that         .

A.people will make every effort to keep it

B.its importance is rarely understood

C.it is something that can easily be lost

D.people don’t cherish it until they lose it

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自由空间的路径中值损耗为()

A.L=32.45+20lgf(ghz)+20lgd(km)

B.L=32.45+20lgf(mhz)+20lgd(km)

C.L=27.55+20lgf(mhz)+20lgd(km)

D.L=27.55+20lgf(ghz)+20lgd(km)

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