用 in, on, under, behind 填空。

     I have a nice and clean room. There is a small desk __1__ the room. My clock is __2__ the desk. The

soccer is __3__ the bed. My backpack is __4__ the door of the room. My pen and eraser are not __5__

the pencil-box. The pencil-box is not __6__ the backpack. It's __7__ the clock.

带有逆转录酶的病毒是（）

A.人类免疫缺陷病毒

B.EB病毒

C.单纯疱疹病毒

D.人 * * 瘤病毒

E.乙型肝炎病毒