1.(-)They didn't decide to leave soon.
(?)Did they decide to leave soon?
2.(+)There were many homeless people here ten years ago.
(?)Were there many homeless people here ten years ago?
3.(+)Tom's grandfather used to be a soldier.
(-)Tom's grandfather didn't use to be a soldier.
4.(-)My teacher didn't start teaching here 6 years ago.
(?)Did your teacher start teaching here 6 years ago?

5,(-)Jane didn't often go to school on foot 3 years ago.

(?)Did Jane often go to school on foot 3 years ago?
6.(+)The cat wanted to eat yesterday.
   (?)Did the cat want to eat yesterday?
7,(+)The train arrived late yesterday.
   (-)The train didn't arrive yesterday.
8.(+)There was anything left in the fridge.
   (?)Was there anything left in the fridge?