layer upon layer
例句里的：
经过一段很长的时间,泥和植物一层又一层地堆积起来,上覆沉积物的巨大重量使这些局部已腐烂的植物遗骸变成了泥炭.
Over a long period of time,[ layer upon layer ]of mud and plants slowly accumulate, one upon the other. The great weight of the overlaying sediments causes the partially rotted plant remains to be changed into peat
在我们面前的是漫山遍野的茶树,从山脚到山顶,一层又一层,连绵起伏,蔚为大观,我抬头看呀看,弄得我脖子酸酸的.
In front of us was a mountain of teas,[ layer upon layer] from the bottom of the mountain up to the top of it, so I had lifted my head high and high till I felt my neck hurt.