(An) apple fell from the tree and hit him on (the) head ?

问题描述:

(An) apple fell from the tree and hit him on (the) head ?
既然有on the head那么 on his head行吗?还有face用 in (in the face )那么什么时候用on 什么时候用in

头,背,鼻子,肩---较硬的人体部分用 on
----反之亦然-----