The present: de tegenwoordige tijd
The present continuous.
How: am/ is/ are werkwoord + ing
I am teaching right now.
David is playing the guitar at the moment.
They are listening to their teacher now.
When: iemand is nu iets/ een activiteit "aan het doen". This activity takes some time and it is temporarily (tijdelijk).
Signaalwoorden: at the moment, right now, now, at this very moment.