榴弾砲: a howitzer

know well, be familiar with, be well informed about

thorough knowledge of

operate (machinery)

maneuver, operate

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

a howitzer

榴弾: a high explosive