单项选择题

The biggest worry that the researchers now have is _______.

A．more and more wild chimpanzees are being slaughtered
B．AIDS virus is difficult to be killed and controlled
C．it is not easy to repair people’s deficient immune systems
D．many dangerous viruses are being transmitted to humans
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单项选择题
Since chimpanzees are genetically very similar to humans, _______.
A．chimpanzees are likely to suffer AIDS just like humans if they are infected
B．it does not matter if human beings are infected with SIV rather than HIV-1
C．we can use human vaccines to prevent chimpanzees from getting AIDS virus
D．AIDS vaccines based on chimp’s immune mechanism are possible to be made
单项选择题
Many AIDS experts are not completely satisfied with results of the study because _______.
A．only a limited number of chimpanzees are used for sampling the virus
B．it is now extremely difficult to find chimpanzees that carry the virus
C．the samples collected are from two different subspecies of chimpanzees
D．it does not provide reliable evidence of the link between SIV and HIV-I
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