Old As Dirt Part 2

I was talking to Nathan about his new teacher yesterday. He is really happy with her and told me so, but then added a "but"...
He said that he thinks she has a nice face and nice hair, and even her arms and her hands are nice, but when she wears shorts (our school does not have a/c) he said that her knees look all shrively.
I laughed and laughed....
and then asked him if my knees are shrively.
He said no.
Whew!