I know a place __ we can have a big meal.
A:that
B:where
C:which
D:what
An hour ago we____ ____ ____ ____it in groups.
已知实数x,y满足y≤xx+2y≤4y≥-2x+12+y-12=r2r>0,则r的最小值为( )
战国时期引起社会变革的最根本因素是( )