- He skinned his knees climbing down the tree.
- He rubbed the skin off his knees climbing down the tree.
- His knees were skinned off while climbing down the tree.
All these sentences OK?
Which one is more natural to the native ears?
#1 is definitely the most natural. #2 is marginal, but sends a shiver down my spine in sympathy when I read it, while #3 is definitely incorrect.
Luschen,
Could you explain how #3 is wrong with its grammar points involved?
You would have to say something like “the skin was skinned off his knees”, but that sounds very redundant.
Luschen,
Can I say: “He skinned out/off his knees climbing down the tree.”?
I would not - the idiom is “skinned his knees”, so if you use skinned in such a similar way, it sounds like you are getting the idiom wrong. Note that “scraped his knees” is also acceptable.