Miss Yellow always asks her students ________.
A:not to stay up late
B:don't stay up late
C:not stay up late
D:don't stay out late
下列各对物质中,一定互为同系物的是( )
设m∈R,命题“若m≤0,则方程x2+x﹣m=0有实根”的逆否命题是( )