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.
