$\text{1. }$

(-) Your friends didn't eat some hamburgers last night.

(?) Did your friends eat some hamburgers last night?

$\text{2. }$

(-) Alex and Chris weren't in Rio in October.

(?) Were Alex and Chris in Rio in October?

$\text{3. }$

(-) Bettina didn't read a whole book yesterday.

(?) Did Bettina read a whole book yesterday?

$\text{4. }$

(-) Clare didn't play tennis this weekend.

(?) Did Clare play tennis this weekend?

$\text{5. }$

(-) David didn't wash his car on Saturday.

(?) Did David wash his car on Saturday? 

$\text{6. }$

(-) Kate didn't finish her homework.

(?) Did Kate finish her homework?

$\text{7. }$

(-) Julia didn't clean the entire house this morning.

(?) Did Julia clean the entire house this morning?

$\text{8. }$

(-) All the students didn't answer the questions.

(?) Did all the students answer the questions?

$\text{9. }$

(-) Marta didn't wait for the bus.

(?) Did Marta wait for the bus?

$\text{- Cấu trúc quá khứ đơn với tobe: }$

(-) S+ was/were+ O/N...

(?) Was/were+ S+ O/N?

+ I/we/they/you/Danh từ số nhiều+ was

+ He/she/ it/ Danh từ số ít+ were

$\text{- Cấu trúc quá khứ đơn với động từ thường: }$

(+) S+Vpp/ed

(-) S+ didn't+V(inf)

(?) Did+S+V(inf)?