— Could you please tell Peter that I want to talk to him?

— Sure, I will let him know as soon as he             back. [ ]

A. comes

B. came

C. has come

D. will come

下面哪种说法正确？（）

A、目前艾滋病不能治愈，也没有有效的疫苗，所以艾滋病是不能预防的

B、安全套可以避孕，但不能预防艾滋病

C、共用注射器吸毒可以感染艾滋病，是因为毒品中有艾滋病病毒

D、正确使用安全套可以预防艾滋病