单项选择题

The second part of the Internet is the" pipes" that carry data, video, e-mail messages, and text from companies such as Google, Hulu, Yahoo !, and Twitter, the millions of websites that make up Internet content and services, to customers. Some of these" pipe" providers, specifically telecom and cable companies, are already complaining that the amount of data that they have to move is rising too rapidly for them to accommodate. Video files, which are particularly large, have posed significant problems to cable companies and they have asked Washington to be able to charge more for customers who use the Internet to transfer large files. So far, the government has turned those requests down.
All the following are mentioned as part of the "pipes" EXCEPT

A. e-mail messages.
B. video.
C. text from companies.
D. cable companies.
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单项选择题
Most viruses that cause swine flu or bird flu are very hard to pass from one human to another: they don’t cause epidemics. Sometimes, however, further changes in genes create a virus that can spread rapidly among humans, and can produce a more severe illness. One reason this illness is more severe is that the virus is so new. The regular flu that comes each year is caused by a regular human influenza virus that often has similarities to the viruses that have caused the nu in years past, so people have some degree of immunity to the latest virus. The unusual swine flu or bird flu viruses that develop the ability for person-to-person spread are so different that people have little or no immunity to them. What is the main reason that the swine flu is very dangerous to humans A. That it is fatal and has killed many. B That it has spread to many countries. C. That people know nothing about it. D. That people have no immunity to it.
Most viruses that cause swine flu or bird flu are very hard to pass from one human to another: they don’t cause epidemics. Sometimes, however, further changes in genes create a virus that can spread rapidly among humans, and can produce a more severe illness. One reason this illness is more severe is that the virus is so new. The regular flu that comes each year is caused by a regular human influenza virus that often has similarities to the viruses that have caused the nu in years past, so people have some degree of immunity to the latest virus. The unusual swine flu or bird flu viruses that develop the ability for person-to-person spread are so different that people have little or no immunity to them.
What is the main reason that the swine flu is very dangerous to humans
A. That it is fatal and has killed many. B That it has spread to many countries.
C. That people know nothing about it. D. That people have no immunity to it.