Chinese chess has a history of more than 2, 000 years. Today it still interests _______ the young _______ the old.
A:both; and
B:either; or
C:not; but
D:neither; nor
人类有许多高尚的品格,但有一种高尚的品格是人性的顶峰,这就是个人的自尊心。一个有自尊心的人 ( )
下列做法中有利于保护金属资源的是( )
(1)f(x1+x2)=f(x1)f(x2)
(2)f(x1•x2)=f(x1)+f(x2)
(3) f(x1)−f(x2)x1−x2 >0
(4)f( x1+x22 )< f(x1)+f(x2)2
(5)f( x1+x22 )> f(x1)+f(x2)2
(6)f(﹣x)=f(x).
当f(x)=lgx时,上述结论正确的序号为____.(注:把你认为正确的命题的序号都填上).