A:3,+∞
B:2,3
C:2,3)
D:2,+∞
——What do you think of your parents?——They are always strict ____ our studies and they often make me ______ too much homework .
某同学观察蜻蜓在贴近平静的水面直线飞行时,获得了一张蜻蜓点水的俯视图片如图所示,图片反映了蜻蜓连续三次点水后某瞬间水面波纹的分布情况(每次点水只形成一个波纹),三个波纹刚好在O点内切,蜻蜓每次点水所用的时间忽略不计,分析图片下列说法中正确的是