2 sentences

1. 他无法自拔地在毒品和赌博中沉沦。

   tā wú​fǎ zì​bá de zài dú​pǐn hé dǔ​bó zhōng chén​lún.

   He is hopelessly sinking into the abyss of drugs and gambling.

   Source: Dong Chinese Dictionary

2. 那个古老的文明最终沉沦在历史的长河中。

   nà gè gǔ​lǎo de wén​míng zuì​zhōng chén​lún zài lì​shǐ de cháng​hé zhōng.

   That ancient civilization eventually perished in the long river of history.

   Source: Dong Chinese Dictionary