hit+ sb.+ on/in + the +身体部位"这样的结构(其中的定冠词不可用物主代词代替).如果打在坚硬结实的部位(如head, shoulder, back等),前面常用介词on;如果打在柔软多肉的部位, (如leg, eye, face等)前面常用介词in.
e.g. hit him on the head/ shoulder/back
hit him in the face /eyes/right leg
hit sb on the head; (硬的表面)
hit sb in the face. (软的可陷入的地方)