After a talk with his mother, the little boy has seen to _____ that the same mistake doesn’t happen again.

A．one

B．it

C．him

D．himself

城市分布在河流沿岸的弊端主要是（　　）

A．河流水患对城市造成损失

B．河流提供充足的水源

C．地形平坦，提供建设用地

D．河流提供便利的水运