Students rate ______ the worst curriculum subject for engagement.

A．Their targets were near Pentagon.
B．Their targets were five miles away from Baghdad.
C．Their targets were below the 32nd parallel.
D．Their targets were near the parallel where Iraqi civilians are not allowed to go.

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