Describe an occassion when you had to do something in a hurry You should say: what you had to do...

Describe a monument( e.g. a statue or sculpture) that you like You should say: what this monument is where this...

Describe a big city you would like to visit. You should say: which big city would you like to visit...

Describe the neighbourhood you lived in when you were a child. You should say: where in your town/city this neighbourhood...

Describe some food or drink that you learned to prepare. You should say: what food or drink you learned to...