11.

If p is a positive odd integer, what is the remainder when p is divided by 4 ?

(1) When p is divided by 8, the remainder is 5.

(2) p is the sum of the squares of two positive integers.

(1) 可以,

(2)?/ 怎么算出来, (2) 不行的, 9+4/4.   25+4/4,  余1,  49+4/4, 余 3

 可是答案给的是D 啊?

p为odd，根据2），可以确定一定是“奇数的平方+偶数的平方”

设p=（2n）^2 +(2m+1)^2