rewrite:

1. Yesterday, I purchased a bunch of flowers for my mother.
2. During the last vacation in Ha Long Bay, our class stayed at this hotel.
3. The day before yesterday, our group delivered a presentation on developing life skills.
4. A tiny sweater was knitted by my grandma for her dog.

make question:

1. Who did you buy a bunch of flowers for yesterday?
2. Where did our class stay during the last vacation in Ha Long Bay?
3. When did our group give a presentation on how to develop life skills?
4. Who did my grandma knit a tiny sweater for?