2 sentences for 势力 (shì​li — influence)

1. 这一带是他的势力范围。

   zhè yī​dài shì tā de shì​li fàn​wéi.

   This area is within his sphere of influence.

   Source: Dong Chinese Dictionary

2. 那个地区的黑社会帮派势力非常大。

   nà gè dì​qū de hēi​shè​huì bāng​pài shì​li fēi​cháng dà.

   The underworld gangs in that area are very powerful.

   Source: Dong Chinese Dictionary