Triggered abilities use the word "when," "whenever," or "at." They're often written as "[Trigger condition], [effect]." Some keywords (such as prowess) are triggered abilities and will use "when," "whenever," or "at" in their reminder text
It is about my vintage cube, what I have observed playing it sometimes now, and what conclusions I think could be made from it
You can play a land only during your main phase when you have priority and the stack is empty
Karador is a more universal creature, whereas Ghave would have been a great fit for Jund, with tokens and sacrifices all over the place
Her ability allows you to put an Angel, Demon, or Dragon Creature into play from your hand whenever you attack