Once infected with HIV, the body is unable to ________ itself against diseases．

Once infected with HIV, the body is unable to ________ itself against diseases．

A.defend

B.judge

C.save

D.prevent

答案及解析： A

解析：

根据句意可知应该是同疾病作斗争，故用defend。prevent意为“阻止”，放在这里与题意不符，因此排除D项。