New strains of viruses are transmitted to man by______. A. a type of pig B. diseased lower

Passage Two

Questions 26 to 30 are based on the following passage.

Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition，man can catch the disease from animals. In fact，a great number of wild birds seem to carry the virus without showing any evidence of illness. Some scientists conclude that a large family of influenza viruses may have evolved in the bird kingdom，a group that has been on the earth 100 million years and is able to carry the virus without contracting the disease. These are even convincing evidence to show that virus strains are transmitted from place to place and from continent to continent by migrating birds.

It is known that two influenza viruses can recombine when both are present in an animal at the same time. The result of such recombinations is a great variety of strains constraining different H and N spikes. This raises the possibility that a human influenza virus can recombine with an influenza virus form. a lower animal to produce an entirely new spike.

Research is underway to determine if that is the way that major new strains come into being. Another possibility is that two animal influenza strains may recombine in a pig，for example，to produce a new strain which is transmitted to man.

According to the passage，scientists have discovered that influenza viruses______.

A. cause ill health in wild birds

B. do not always cause symptoms in birds

C. are rarely present in wild birds

D. change when transferred from animals to man

According to the passage，a great variety of influenza strains can appear when______.

A. H and N spikes are produced

B. animal and bird viruses are combined

C. dissimilar types virus recombine

D. two viruses of the same type are contracted

What is known about the influenza virus？

A. It was first found in a group of very old birds.

B. All the different strains can be found in wild birds.

C. It existed over 100 million years ago.

D. It can survive in many different places.

A. two influenza viruses in the same animal recombining

B. animal viruses recombining with human viruses

C. two animal viruses recombining in one animal

D. two animal viruses recombining in a human

A. Incident response

B. Asset management

C. Patch management

D. Policies and procedures

There are three main types of influenza virus. The most important of these are types A and B, each of them having several sub-groups. With the instruments at the hospital the doctor recognized that the outbreak was due to a virus group A, but he didn't know the sub-group. He reported the outbreak to the World Health Organization in Geneva. WHO published the important news alongside reports of a similar outbreak in Hong Kong, where about 15%～20% of the population had become ill.

As soon as the London doctors received the package of throat samples, they began the standard tests. They found that by reproducing itself at very high speed, the virus had multiplied more than a million times within two days. Continuing their careful tests, the doctors checked the effect of drugs used against all the known sub-groups of type A virus. None of them gave any protection. This then, was something new; a new influenza virus against which the people of the world had no ready help whatsoever.

Having isolated the virus they were working with, the doctors now conducted tests on some specially selected animals, which contracted influenza in the same way as human beings did. In a short time the usual sign of the disease disappeared. Theses experiments revealed that the new virus spread easily, but that it was not a killer. Scientists, like the general public, called it simply "Asian" flu.

The influenza discovered by a doctor in Singapore is caused by ______.

A．a new type of virus

B．type A virus

C．a sub-group of type B virus

D．a virus only existing in Asia

A. Perform a full system backup.

B. Follow up with the customer, verifying satisfaction.

C. Ask their manager to contact the customer.

D. Perform a complimentary virus scan.

A.General to Specific

B.Problem to Solution

C.Process

D.Old to New

A．Less than 8%．

B．About 9.5%．

C．1.5%．

D．17.5%．

A.General to Specific

B.Problem to Solution

C.Process

D.Old to New