a. I wasn't/weren't at home last week

=> $ wasn't $

b. You was / were very kind yesterday

=> $ were$

c. It was / were cold last night

=> $was$

d. My parents were / wass at the supermarket this morning

=> $were$

e, David wasn't / weren't happy yesterday

=> $ Wasn't $

f. We was / were late this morning

=>  $Were$

g. My friends wasn't / weren't at the park this afternoon

=> $weren't$

i. The weather was / were very hot yesterday

=> $was$

j.I was/were happy yesterday.

=> $was$

k. The boy was / were at the store 

=> $ was $

o. My grandparents was / were at home yesterday

=> $ Were $

Giai thích :

+ Từ $ was $ dành cho những từ : she , he , my , it ( danh từ số ít )

+ Từ $ were $ dành cho những từ : we , they , you ( danh từ số nhiều )

`bb( Answer) ` 

Cấu trúc thì quá khứ đơn với tobe : 

` ( + )` : S + was / were + ... 

` ( - )` : S + was / were + not + ... 

` ( ? )` : Was / Were + S + ... ? 

` - ` I / he / she / it / chủ ngữ số ít + was ( not ) + ... 

` - ` You / We / They / chủ ngữ số nhiều + were ( not ) + ... 

` a ` . wasn't 

` b ` . were 

` c ` . was 

` d` . were 

`e ` . wasn't 

` f ` . were 

` g ` . weren't 

` i ` . was 

` j ` . was 

` k ` . was 

` o ` . were