1, Liz didn't buy many souvernirs in HCM city.

  Did liz buy many souvernirs in HCM city?

2, i was not very tired after the trip

  Were you very tired after the trip?

3, they are not watching my father 's new motobike

 Are they watching my father 's new motobike?

4, We did not visit cham temple last month.

   Did we/they visit cham temple last month?

5, trung's brother does not go on holiday in HLb every summer

  Does trung's brother go on holiday in HLb every summer?

=>

1. (-) Liz didn't buy many souvenirs in Ho Chi Minh City.

(?) Did Liz buy many souvenirs in Ho Chi Minh City?

2. (-) I wasn't very tired after the trip.

(?) Was you  tired after the trip?

3. (-) They aren't watching my father's new motorbike.

(?) Are they watching my father's new motorbike?

4. (-) We didn't visit Cham Temple last month.

(?) Did you visit Cham Temple last month?

5. (-) Trung's brother doesn't go on holiday in Ha Long Bay every summer.

(?) Does Trung's brother go on holiday in Ha Long Bay every summer?