4 sentences

1. 长江下游的地区非常繁荣。

   Cháng Jiāng xià​yóu de dì​qū fēi​cháng fán​róng.

   The regions in the lower reaches of the Yangtze River are very prosperous.

   Source: Dong Chinese Dictionary

2. 洪水汤汤，席卷了下游的村庄。

   hóng​shuǐ shāng shāng, xí​juǎn le xià​yóu de cūn​zhuāng.

   The torrential floodwaters swept through the downstream villages.

   Source: Dong Chinese Dictionary

3. 如果大坝决堤，下游的村庄就会遭殃。

   rú​guǒ dà​bà jué​dī, xià​yóu de cūn​zhuāng jiù huì zāo​yāng.

   If the dam breaks, the downstream villages will suffer.

   Source: Dong Chinese Dictionary

4. 他的成绩在班里一直处于下游。

   tā de chéng​jì zài bān lǐ yī​zhí chǔ​yú xià​yóu.

   His grades have always been in the bottom tier of the class.

   Source: Dong Chinese Dictionary