knees

例句:

• Breathe out and ease your knees in toward your chest.
  呼气，膝部放松向胸部靠拢。
  
• I went down on my knees and prayed for guidance.
  我跪了下来，祈求得到指引。
  
• Mcanally's knees buckled and he crumpled down onto the floor.
  麦卡纳利双膝发软，瘫倒在地板上。
  
• First with fist, then boots, then knees.
  来自BBC
• Both players bumped knees and tumbled to the grass.
  来自WSJ
• Maybe I can help them not skin their knees.
  来自WSJ