A:y2=16x
B:x2=﹣8y
C:y2=16x或x2=﹣8y
D:y2=16x或x2=8y
竞争是基于一定规则进行的,我们在竞争中必须遵守的基本准则是( )
从繁殖的角度看,一朵花主要的结构是雌蕊和雄蕊。
She is ____ (luck) to have a lot of friends to help her.