据说四肢爬行对人的健康有利。
It is said that crawling on all fours brings benefits to human 's health .
其余的不是瞎子就是跛子，所以他们得用手来爬行。另外有些人手臂发育不全，手上连手指也没有。
the others were either blind , had withered legs and crept about on their hands , or withered arms and fingerless hands .
爬行人