DUM clauses

The present tense is used far more frequently in Latin than it is in English (at least in literary prose) as a lively representation of the past; this is called the HISTORICAL PRESENT:

DUM clauses:  "while" uses the INDICATIVE:

Dum haec in colloquio geruntur, Caesari nuntiatum est .   (Caesar Bellum Gallcum I. 46.1)
"While these things were being transacted in the conference, a message was brought to Caesar"

Conjunctions which are used to indicate 'contemporaneous action' in Latin are: dum, donec ('while, so long as, until), quoad ('up to the time that'), quamdiu ('as long as') and cum ('when')

Vita, dum superest, bene est.
'As long as life remains, it is well.'

Fuit haec gens fortis, dum Lycurgi leges vigebant.
'This people was strong, so long as the laws of Lycurgus were in force.'

Exspectabo dum venit.
'I will wait until he comes.'

DUMMODO clauses:   'dummodo proviso'   'provided that' uses the SUBJUNCTIVE:

Oderint dum metuant. (Accius, quoted in Cicero de officiis I. 28.97)
"Let them hate (me) as long as they fear (me)."