嚓嚓地割下树枝

swish off the branches of a tree

上楼时嚓嚓的脚步声

the scrape of footsteps up the stairs

狗嚓嚓地抓门要想进来。

A dog scratched at the door to be let in.

他听到有人上楼的嚓嚓的脚步声。He scraped through the narrow opening。

He heard the scrape of footsteps up the stairs.