I have one ruler and he has one eraser.
我有一把尺，他有一块橡皮。
I have a new eraser. It's a fish.
我有一块新橡皮，它是鱼。
Now where did my eraser go this time?
这回我的橡皮又到哪去了？
If you need to change what you wrote, just use this eraser.
如果你需要更改所写的'内容，就用这块橡皮擦。
Pass me your eraser to make the board clean.
把你的擦子递给我，我来把黑板擦干净。