任意两个数的和比差大对不对简介：Liu Lei grinned, that's right. He was about to say something, but suddenly there was a librarian, an old man, tilting his head and looking up, shouting, "Who's up there?" Come down quickly, don't stay up there!
Liu Lei grinned, that's right. He was about to say something, but suddenly there was a librarian, an old man, tilting his head and looking up, shouting, "Who's up there?" Come down quickly, don't stay up there!
