狗又在抓门了；它肯定想出去。

The dog is ___scratching at the door again; it must want to go out.

我听到从旧橱柜里传来一种奇怪的刮擦声。

I heard a strange ___scratching noise coming from inside the old cupboard.

我的猫喜欢在桌子的木腿上磨爪子。

My cat loves to ___scratch its claws on the wooden leg of the table.