— Tomorrow we'll have an English exam. I'm worried about it.
— _______ You will do better.
A:Cheer up.
B:Hurry up.
C:By the way.
D:Take it easy.
如图是一农田长期使用一种农药后害虫群体密度变化曲线.不符合达尔文进化观点的是( )
二项式x+2x12 展开式中的常数项是( )
周长相等的两个圆,它们的面积也一定相等.