读东北区自然地理环境概况分布图,回答下列问题: (1)写出山脉的名称: A_____________________ B____________________ C____________________ (2)写出河流的名称: D____________________E____________________ F____________________ G_____________________ (3)写出平原的名称: 甲____________________ 乙____________________ 丙____________________ |