副词作表语很常见。主要指主语的方向、方位、动作情况或状态等。

Is anybody in?里边有人吗？

Sorry，I have to be off right now. 对不起，我得马上走。

The light is on. 灯亮着。

They are all abroad. 他们都出国了。

The war was over. 战争结束了。

可作表语的副词：in, on, off, out, away, behind, up, down, over, through, around, round, below, inside, outside,  here，there, over there, over，upstairs，downstairs，indoors，outdoors，等。