(like) water off a duck's back 鸭子身上的毛就像雨衣一样，水在上面呆不住，一下全滑掉了。因此，water off a duck's back 是指毫无作用。 criticisms of or warnings to a particular person that have no effect on that person (批评或警诫对某人)像水过鸭背，毫无影响，不起作用 I've told him that he's heading for tro