问题详情

请根据短文的内容，回答题。
Centers for Disease Control
One of the major health agencies in the United States is the Centers for Disease Control and Prevention. It is known as the C-D-C. "Prevention" was added __________ (51) the name later. The agency has many jobs. For example, it recently __________ (52) information to the public about ricin (蓖麻毒素) . Some of that poison had been found in a Senate office building in Washington. The C-D-Cadvised people about ways to stay __________ (53) if they ever found ricin.<br>
The C-D-C warns, advises and reports on health subjects from around the world. For example,it is currently providing information about avian influenza. The __________ (54) of bird flu in Asia has killed more than twenty people in Thailand and Vietnam.<br>
The agency also is advising people __________ (55) to protect against cold weather and__________ (56) heated homes in winter. And the C-D-C just gave Americans the newest estimate of how long they can expect to __________ (57). In two-thousand-two, average life expectancy reached seventy-seven-point-four years. __________ (58) the C-D-C also reported an increase in the rate of deaths among newborn babies that year. It was the first__________ (59) in the United States since nineteen-fifty-eight.<br>
The Centers for Disease Control and Prevention is an agency within the Department of Health and Human Services. Its main offices and laboratories are in Atlanta, Georgia.<br>
Eight-thousand-five-hundred people work __________ (60) the C-D-C. These __________ (61)doctors, nurses, scientists, engineers and others. They all have some part in trying to learn how diseases start, and where and how they spread.<br>
C-D-C laboratories examine tissue, blood and other substances to help __________ (62) diseases. For example, the C-D-C recently confirmed the presence in Bangladesh of a viral infection similar to the Nipah virus. This virus was first recognized in nineteen-ninety-nine in Nipah, Malaysia. It was __________ (63) widespread cases of encephalitis (脑炎), a brain infection. More than one-hundred people __________ (64) the disease.<br>
C-D-C experts are __________ (65) to travel anywhere in the world to help deal with<br>
outbreaks of disease. The faster the cause is identified, the faster health workers can take steps to contain and control it.
__________ 查看材料
A.on
B.in
C.upon
D.to请帮忙给出正确答案和分析，谢谢！