3 sentences

1. 我怎么知道你不是执法人员呢？

   wǒ zěn​me zhī​dào nǐ bù shì zhí​fǎ rén​yuán ne?

   How do I know you're not law enforcement?

   Source: OpenSubtitles

2. 他从事执法工作已经二十多年了。

   tā cóng​shì zhí​fǎ gōng​zuò yǐ​jīng èr​shí​duō nián le.

   He has been working in law enforcement for over twenty years.

   Source: Dong Chinese Dictionary

3. 警察在执行任务时必须严格执法。

   jǐng​chá zài zhí​xíng rèn​wu shí bì​xū yán​gé zhí​fǎ.

   Police must strictly enforce the law while performing their duties.

   Source: Dong Chinese Dictionary