The teacher asked the students who accumulate random stuff of what you have got with the sentence What?, students practice sentences, I have got a reply with a sticker collection.
Random teacher asked the students if anyone's collection of objects with sentences What have you got? Students then answered with a sentence I have got a sticker collection.
The teacher asked the students who were taking what sentences with What have you got? And let students answer sentences I have got a sticker. Collection.