perilous rock的用法和样例：
例句
- So,from the great cliff's base,jut spokes of rock crossing from bank to bank,intersecting ditches until the pit's hub cuts them off from meeting.
就像这样从岩石的基础有危岩通出去而跨越堤岸和壕沟，降到那把它们截断和集合起来的井。 - To control the unstable rock, a thorough study is needed as to the geological status of the road's side slope and the causes of the rock's unstableness.
在治理过程中，需要对公路边坡的地质情况，危岩的发育成因，做出较为透彻的研究。
