例句與造句

1. railway jacking bridge engineering passing through sand pebble ( gravel ) layer, because it is a complex loose coarse fragment accumulation layer, the roadbed must be reinforced
   摘要鐵路頂橋工程中遇到砂卵（礫）石層時(shí)，因砂卵（礫）石層是一種復(fù)雜松散粗碎屑堆積層，因此必須對(duì)鐵路路基進(jìn)行加固。
2. It's difficult to find accumulation layers in a sentence. 用accumulation layers造句挺難的