如图13－24所示，一半径为r的非常小的圆环，在初始时刻与一半径为r’（r’》r)的很大的圆环共面而且同心，今在大环

What's the passage mainly about？

A．American efforts in dealing with brown-fields.

B．The damage caused by brown-fields.

C．The consequence brought about by brown-fields.

D．Financial assistance and brown-fields.

What’s the negative consequence brought about by new communications technology？

A．People lose their intimacy of interaction

B．We can use email and instant messaging over the Internet．

C．We can use voice mail．

D．Almost every conceivable contact between human beings gets automate

D．

on. You will be asked to evaluate the grades mutually. Technological progress has brought great changes to our society in the last 100 years. However, some people think that it has also brought some negative effects at the same time. What’s your opinion？

What is the purpose of a comparison/contrast essay？

A．To testify the accuracy of the author ’ s judgement

B．To illustrate the consequence brought by differences

C．To clarify the two things compared or contraste

D．To foreshadow for the author ’ s conclusion

What is the author's attitude toward changes brought on by technological innovation？

A．He is excited about them.

B．He is disturbed by them.

C．He questions their usefulness.

D．He accepts them as natural.

What is the author's attitude toward changes brought on by technological innovation？

A．He is excited about them.

B．He is disturbed by them.

C．He questions their usefulness.

D．He accepts them as natural.

What is the author's attitude toward changes brought on by technological innovation？

A．He is excited about them.

B．He is disturbed by them.

C．He questions their usefulness.

D．He accepts them as natural.

What ______ this damage？

A．has brought to

B．brought up

C．has brought in

D．brought about

What ______ this damage？

A．has brought to

B．brought up

C．has brought in

D．brought about