2) I stayed in New Zealand for six months.

-> How long have you stayed in New Zealand ?

3) She called the firemen because her cat stuck in a tree .

-> Why did she call the fireman ?

4) I bought two kilos of oranges.

-> How many kilos of oranges did you buy ? 

5) John wrote about his grandparents.

->  Who did John write about ?

1.I stayed in New Zealand for six months
2.Why did she call the firemen?
3.How many kilos of oranges did you bought?
4.About whom did John write?