This is the 3131st most frequent Dutch word.
durend
"Durend" means "lasting" or "ongoing" in English.
Here, 'durend' is used as an adjective, describing an ongoing state (the lesson).
De les is nog steeds durend.
The lesson is still ongoing.
In this sentence, 'durend' is also an adjective, qualifying 'verblijf' (stay) to indicate its ongoing nature.
Zij gaven elkaar liefde tijdens hun durend verblijf.
They shared love during their ongoing stay.
The word 'durende' is used to describe a continual aspect of 'tijden' (times).