Phần 1: 
 * (+) They decided to leave soon.
   (-) They didn't decide to leave soon.
   (?) Did they decide to leave soon?
 * (+) There were many homeless people here ten years ago.
   (-) There weren't many homeless people here ten years ago.
   (?) Were there many homeless people here ten years ago?
 * (+) Tom's grandfather used to be a soldier.
   (-) Tom's grandfather didn't use to be a soldier.
   (?) Did Tom's grandfather use to be a soldier?
 * (+) My teacher started teaching here 6 years ago.
   (-) My teacher didn't start teaching here 6 years ago.
   (?) Did my teacher start teaching here 6 years ago?
 * (+) Jane often went to school on foot 3 years ago.
   (-) Jane didn't often go to school on foot 3 years ago.
   (?) Did Jane often go to school on foot 3 years ago?
 * (+) The cat wanted to eat yesterday.
   (-) The cat didn't want to eat yesterday.
   (?) Did the cat want to eat yesterday?
 * (+) The train arrived late yesterday.
   (-) The train didn't arrive late yesterday.
   (?) Did the train arrive late yesterday?
 * (+) There was nothing left in the fridge.
   (-) There wasn't anything left in the fridge.
   (?) Was there anything left in the fridge?
Phần 2: 
 * Last week, my mother (take) took me to the zoo.
 * When we (arrive) arrived at the party, there (not be) wasn't many people there.