Eachhandportable，semi-portableandfixedfireextinguishingunitonashipmustbetestedandinspectedatleastonceevery（）. A: sixweeks B: sixmonths C: twelvemonths D: twoyears
Eachhandportable，semi-portableandfixedfireextinguishingunitonashipmustbetestedandinspectedatleastonceevery（）. A: sixweeks B: sixmonths C: twelvemonths D: twoyears
1