请帮忙分析这句的语法(英语)Most of us thought the sand had come form an a
请帮忙分析这句的语法(英语)
Most of us thought the sand had come form an ancient mountain range fairly close by that flattened out over time.
这句中,fairly close by 是修饰 mountain range对吗?那么,后面那个that从句是修饰谁呢?或者是,close by that 本身就是连在一起的?我迷糊了!英语达人请帮忙分析这句话的精确语法.