When
pronoun
He eats (いつ) and eats and eats. When does this guy not eat? いつ is a question word that is used to ask when.
いつする
when to do something
いつやる
いつのもの
a thing from when
いつのやつ
stuff from when
いつのヨーグルト
yogurt from when
いつから
from when
いつまで
until when
いつするの？
When will you do it?
いつまでアメリカ？
Until when are you in the U.S.?
いつからカナダ？
From when will you be in Canada?