My brother ____ (do) his homework every evening.
我国一、二阶梯的分界线是大兴安岭﹣太行山脉﹣巫山﹣雪峰山.
一只水鸟在平静的水面上飞过,当水鸟距离水面3m时,它在水面的“倒影”是 ____(填“实”或“虚”)像.