Use "on active service" in a sentence

1. In April 1944 he was killed on active service.

2. 1943 (JUL.2.) registered cover addressed to Pretoria bearing Basutoland 1/2d, 1d, 1 1/2d, 2d (x2) and 4d adhesives making up a 1/2d rate marked 'On Active Service' and cancelled by EGYPT/104/ POSTAGE PREPAID cancels used by South African Forces.