猜一猜,写一写,画一画.
问题描述：
猜一猜,写一写,画一画.
1．It is clean when it is black.
It is dirty when it is white.
What's it?
2.It has a long body.
It has a black heart.
It walks on paper.
It becomes shorter and shorter.
What's it?
答
1.blackboard黑板
2.pencil铅笔