已知2x2+y2=1 ,则2x+y的最大值是( )
A:2
B:2
C:3
D:3
Tom is not late school. It's Saturday today.
同在一个屋檐下,同学间发生小矛盾、小摩擦在所难免。下列做法不利于解决矛盾、化解冲突的是( )