生长激素的药物刺激试验包括________、________、________、__

在下列铁的化合物中，铁元素的质量分数最高的是 [ ]

A．FeO　　　　　　

B．Fe₂O₃　　　　

C．Fe₃O₄　　　　　　

D．FeS

Professor Barry Wellman of the University of Toronto in Canada has invented a term to describe the way many North Americans interact(互动)these days.The term is “networked individualism”.This concept is not easy to understand because the words seem to have opposite meanings.How can we be individuals(个体)and be networked at the same time?You need other people for networks.

Here is what Professor Wellman means.Before the invention of the Internet and e-mail,our social networks included live interactions with relatives,neighbors,and friends.Some of the interaction was by phone,but it was still voice to voice,person to person,in real time.

A recent research study by the Pew Internet and American Life Project showed that for a lot of people,electronic interaction through the computer has replaced this person-to-person interaction.However,a lot of people interviewed for the Pew study say that’s a good thing.Why?

In the past,many people were worried that the Internet isolated(孤立)us and caused us to spend too much time in the imaginary world of the computer.But the Pew study discovered that the opposite is true.The Internet connects us with more real people than expected—helpful people who can give advice on careers,medical problems,raising children,and choosing a school or college.About 60 million Americans told Pew that the Internet plays an important role in helping them make major life decisions.

Thanks to the computer,we are able to be alone and together with other people—at the same time!

小题1:The underlined phrase “networked individualism”probably means that by using computers people_______.

A．stick to their own ways no matter what other people say

B．have the rights and freedom to do things of their own interest

C．do things in their own ways and express opinions different from other people

D．are able to keep to themselves but at the same time reach out to other people小题2:According to the Pew study,what do many people rely on to make major life decisions?

A．Networks.

B．Friends.

C．Phones.

D．Parents.小题3:It can be inferred from the Pew study that_______.

A．people have been separated from each other by using computers

B．the Internet makes people waste a lot of time and feel very lonely

C．the Internet has become a tool for a new kind of social communication

D．a lot of people regard the person-toperson communication as good thing小题4:Which would be the best title for this passage?

A．We’re Alone on the Internet.

B．We’re Communicating on the Internet.

C．We’re Alone Together on the Internet.

D．We’re in the Imaginary World of the Internet.

如图所示,左图是游乐场中过山车的实物图片,右图是过山车的原理图.在原理图中半径分别为R₁="2.0" m和R₂="8.0" m的两个光滑圆形轨道,固定在倾角为α=37°斜轨道面上的Q、Z两点,且两圆形轨道的最高点A、B均与P点平齐,圆形轨道与斜轨道之间圆滑连接.现使小车（视作质点）从P点以一定的初速度沿斜面向下运动.已知斜轨道面与小车间的动摩擦因数为μ=,g="10" m/s²,sin37°=0.6,cos37°=0.8.问:

（1）若小车恰好能通过第一个圆形轨道的最高点A处,则其在P点的初速度应为多大?

（2）若小车在P点的初速度为10 m/s,则小车能否安全通过两个圆形轨道?

在进行一次有关龋病危险因素的流行病学问卷调查时，由于调查对象对于家庭收入的问题不愿意真实回答，使结果产生误差，这种偏倚称为（）。

A.报告偏倚

B.回忆偏倚

C.测量偏倚

D.无应答偏倚

E.选择性偏倚

土壤 * * 后，其热容量和导热率变大，所以土壤表面温度日较差变大。