1.They watched television last night.
Negative: They didn't watch television last night.
Interrogative: Did they watch television last night?
2.She bought some flowers for her mother's birthday.
Negative: She didn't buy some flowers for her mother's birthday.
Interrogative: Did she buy some flowers for her mother's birthday?
3.Mr.Tan taught us physical education last year.
Negative: Mr.Tan didn't teach us physical education last year.
Interrogative: Did Mr.Tan teach you physical education last year?
4.He spent little time playing sports.
Negative: He didn't spend little time playing sports.
Interrogative: Did he spend little time playing sports?