A:获得食物
B:找到配偶
C:判断行为
D:适应复杂环境
如图所示,在平面直角坐标系xOy中,点B,C分别在x轴和y轴非负半轴上,点A在第一象限,且∠BAC=90°,AB=AC=4,那么O,A两点间距离的( )
Look! The panda is so ____. It's _____ than both of us.