96. The time during which an act takes place or a condition exists may
be expressed not only by an adverb or accusative of time (91), or by use
of the preposition "dum", but also by a clause introduced by "dum":
Li venis dum vi forestis,
he came while (during-the-time-that) you were away.
Dum la sezonoj malpacis, ili forgesis pri la mondo,
while the seasons quarreled, they forgot about the world.
Ni ridas pro gxojo dum negxas,
we laugh for joy while it is snowing.