YOU SAID:

I used to kill many people in the army

INTO JAPANESE

私は軍隊で多くの人を殺しました

BACK INTO ENGLISH

I killed many people in the army

INTO JAPANESE

軍隊で多くの人を殺した

BACK INTO ENGLISH

killed a lot of people in the army

INTO JAPANESE

軍隊で多くの人を殺した

BACK INTO ENGLISH

killed a lot of people in the army