一个袋子里有红、黄、蓝色的袜子各10只，则最少要拿多少只才能保证其中至少有两双颜色不相同的袜子？为什么？
13只
— Do you have _____ special to tell me today?
— No, _____. [ ]
A. something, anything
B. nothing, anything
C. anything, something
D. anything, nothing
加热醋酸法尿蛋白定性，结果呈明显白色颗粒状混浊，但无絮状沉淀，应判为( )
A．±B．+C．++D．+++E．++++
