CUM + Indicative = When (present, future) When/While (Perfect, Imperfect, Pluperfect)
CUM + Subjunctive = Since/Because,
Although (often includes tamen)
CUM TEMPORAL CLAUSE ( cum= when)
If the main verb is Primary (Present, Future, Future Perfect) and relates to present or future time,
cum takes the Indicative mood. This type of clause most often describes precise time.
Cum doceo vos, felix sum
When I am teaching you all, I am happy.
CUM CIRCUMSTANTIAL CLAUSE (cum = when, while)
If the main verb is Secondary (Imperfect, Perfect, Pluperfect), relates to past…