直径为d，长度为ι的管道，在层流范围内流量Q增大时，沿程阻力系数λ和沿程水头损失hf的变化为()。

A. VLANs allow access to network services based on department, not physical location.

B. VLANs utilize packet filtering to enhance network security.

C. VLANs provide a low-latency, high bandwidth internetworking alternative.

D. VLANs provide a method of communication between IP addresses in large networks.

E. VLANs establish segmented broadcast domains in switched networks.

F. VLANs can greatly simplify adding, moving, or changing hosts on the network.

Which of the following could probably be the title of the passage？

A．Who Can Benefit from the Fund？

B．Bridging the Gap Between Dreams and Reality.

C．How the United Negro College Fund？

D．Introduction to an Education Support Organization.

What benefit could the students get from the activities？

A．Earning money.

B．Being good on resumes.

C．Providing chances.

D．Improving scores.

Which of the following could probably be the title of the passage？

A．Who Can Benefit from the Fund.

B．Bridging the Gap Between Dreams and Reality.

C．How the United Negro College Fund Operates.

D．Introduction to an Education Support Organization.

How can reading the newspaper, visiting the public library benefit us？

A．Staying mentally healthy.

B．Taking part in social activities.

C．Gaining more knowledge about society.

D．Having more contacts with the outside world.

— How could they keep us witing for so long — They got on the bus hlfn hourgond they ______— How could they keep us witing for so long — They got on the bus hlfn hourgond they ________ be here in ten minutes, I think.might B．would C．should D．must

A．might

B．would

C．shoul

D．must

Which of the following could NOT get benefit from the devaluation of U. S. dollar？

A．Foreign visitors in the U.S.

B．Foreign investors.

C．Exporters of America.

D．American visitors to other countries.

How can reading the newspaper, visiting the public library benefit us？

A．Staying mentally healthy.

B．Taking part in social activities.

C．Gaining more knowledge about society.

D．Having more contacts with the outside world.

What did the speaker want to tell us in this passage？

A．One can benefit a lot from working with his father.

B．Manual labourers shouldn't be looked down upon.

C．One should always do his job earnestly.

D．Teenagers tend to be careless.

What others can benefit from Paula's experience？

A．They could learn Paula's sticking to her dreams.

B．They could find a partner before starting a business.

C．They should watch their steps in business.