In Dutch, when do you know when to say Het or De?

1.apartheid excluded majority of south africans
2.members of resistance were often ill treated in prisons and effects of it spred on their famillies
3.when some protester was killed due to police action it often was only employed person in the familly which led to lack of income
4.accidental vitims of street war
5.separation of famillies
6.sowing distrust in teh communities