与-12符号相反的数是12,所以-12的相反数是12;
故选B.
风险的大小由未来可能收益率与期望收益率的偏离程度来反映。在数学上,这种偏离程度由收益率的方差来度量。 ( )
— It's nice day, isn't it?
— Yes, what fine weather! [ ]
A. a ; a
B. the ; the
C. a ; /
D. the ; /