我觉得碰到这样的题就是分别把条件代入题干，看是否满足，当不确定是否满足（即不容易证明时），可看是否有反例。
13。For any positive integer x, the 2-height of x is defined to be the greatest nonnegative integer n such that 2^n is a factor of x. If k and m are positive integers, is the 2-height of k greater than the 2-height of m ?
(1) k > m
(2) k/m is an even integer.
(1)k>m，不一定the 2-height of k greater than the 2-height of m ，比如k=6时， 2-height of k 为2，m=2时， 2-height of m 为2
(2)设k/m=2t,那必然the 2-height of k 比the 2-height of m大1 | 
