1. 
(-) They didn't decide to leave soon
(?) Did they decide to leve 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 isn't started teaching here 6 years ago
(?) Is my teacher started teaching here 6 years ago?
5.
(-) Jane didn't often go to school on foot 3 years ago