Usages of quis
Mater rogat quis sacculum aperuerit et quis nummos ex eo tulerit; nemo respondet.
Mother asks who opened the bag and who took the coins from it; no one answers.
Ego nescio quis verum dicat, sed omnes sperant rem sine mora finem habituram esse.
I do not know who is telling the truth, but everyone hopes that the matter will come to an end without delay.
Elon.io is an online learning platform
We have an entire course teaching Latin grammar and vocabulary.