—Where are your brothers?
— in the classroom now.
A:He is
B:There are
C:They are
D:We are
分析右图,甲、乙、丙分别表示传染病传播过程中的
下列能使高猛酸钾溶液褪色的是( )
若函数f(x)=ax2+1,x≥0x3,x<0,则不等式f(a)>f(1-a)的解集为( )
下列各数中,是无理数的( )