3 sentences

1. 汉水是长江最长的支流。

   Hàn shuǐ shì Cháng Jiāng zuì cháng de zhī​liú.

   The Han River is the longest tributary of the Yangtze River.

   Source: Dong Chinese Dictionary

2. 灞河是渭河的一条重要支流。

   Bà hé shì Wèi Hé de yī tiáo zhòng​yào zhī​liú.

   The Ba River is an important tributary of the Wei River.

   Source: Dong Chinese Dictionary

3. 河流在这里形成了一个岔，分成了两条支流。

   hé​liú zài zhè​lǐ xíng​chéng le yī gè chà, fēn​chéng le liǎng tiáo zhī​liú.

   The river forks here, splitting into two tributaries.

   Source: Dong Chinese Dictionary