n.基礎(chǔ)；根據(jù)；下層；底層
The story has a substratum of truth. 這故事有事實的基礎(chǔ)。
There is a substratum of truth in her story. 她敘述中有事實根據(jù).
The soil has a substratum of rock. 這土壤下面有層石頭。
