4 sentences

1. 战争导致许多人沦为难民。

   zhàn​zhēng dǎo​zhì xǔ​duō rén lún​wéi nàn​mín.

   The war caused many people to become refugees.

   Source: Dong Chinese Dictionary

2. 如果不悬崖勒马，他迟早会沦为阶下囚。

   rú​guǒ bù xuán​yá​lè​mǎ, tā chí​zǎo huì lún​wéi jié​xià​qiú.

   If he doesn't pull back from the brink, he will sooner or later end up a prisoner.

   Source: Dong Chinese Dictionary

3. 在旧社会，许多贫苦女子被迫沦为妓女。

   zài jiù shè​huì, xǔ​duō pín​kǔ nǚ​zǐ bèi​pò lún​wéi jì​nǚ.

   In the old society, many poor women were forced into prostitution.

   Source: Dong Chinese Dictionary

4. 那个国家曾经非常富裕，现在却沦为世界上最贫穷的国家之一。

   nà gè guó​jiā céng​jīng fēi​cháng fù​yù, xiàn​zài què lún​wéi shì​jiè shàng zuì pín​qióng de guó​jiā zhī​yī.

   That country used to be very wealthy, but it has now fallen into being one of the poorest in the world.

   Source: Dong Chinese Dictionary