cause (source or reason of an event or action)

utmost, full power

analysis, investigation

determine, ascertain

accident; incident; trouble

(slang) (of an incident) to occur

To exhaust; deplete; use up. / serve, assist

to do to exhaustion, to do something completely

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