2 sentences for 役 (yì — service)

1. 他在越战中服过役。

   tā zài Yuè​zhàn zhōng fú guo yì.

   He served in the Vietnam War.

   Source: Dong Chinese Dictionary

2. 他在艰苦的边疆地区服役了整整三年。

   tā zài jiān​kǔ de biān​jiāng dì​qū fú yì le zhěng​zhěng sān nián.

   He served in the military in the harsh border regions for three whole years.

   Source: Dong Chinese Dictionary