gnaw a file

例句：

1. 1. The dog gnaws at the bone all night.
   狗整晚都在啃骨头。
2. 2. The children were gnawling on the bones.
   孩子们正在啃骨头。
3. 3. She gnawed her way through the tough steak.
   她用牙齿把硬牛排啃断了。