on his knees

• adj. 跪着(在严重的状态中)

on his knees的用法和样例：

例句

1. He fell on his knees (ie knelt down) and begged for mercy.
   他跪下求饶。
2. He's down on his knees, scrubbing (away).
   他跪在地上擦洗(起来).