A:唐高祖李渊
B:唐太宗李世民
C:隋文帝杨坚
D:唐玄宗李隆基
函数fx=4-x+lgx-1+x-20的定义域为( )
玲玲家今年前6个月的电话费是480元。照这样计算,她家一年的电话费是多少元?
—Would you please help me _______, Wang Fei? This question is too hard for me.
—OK. Let me have a try.
西周时期的王位世袭制与夏商时期相比,最突出的特点是( )