`12.` were (last year: DH thì QKĐ)

`13.` bought (two days ago: DH thì QKĐ)

`14.` played (last week: DH thì QKĐ)

`15.` was (last year: DH thì QKĐ)

`16.` went (three days ago: DH thì QKĐ)

`17.` visited (last Sunday: DH thì QKĐ)

`18.` didn't go (yesterday: DH thì QKĐ)

`19.` was (in 1980: DH thì QKĐ)

`->` Cấu trúc thì Quá khứ đơn:

`-` với động từ:

`(+)` S + Ved/V2

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

`(?)` Did + S + V?

`-` với tobe:

`(+)` S + was/were                                                                              

`(-)` S + wasn't/weren't

`(?)` Was/Were + S...?

`12.` were

Giải thích: last year `=>` thì QKĐ đối với tobe

$\text{(+) S + was/were + ...}$

`13.` bought

Giải thích: two days ago `=>` thì QKĐ

$\text{(+) S + Ved/V2 + ...}$

`14.` played

Giải thích: last week `=>` thì QKĐ

$\text{(+) S + Ved/V2 + ...}$

`15.` was

Giải thích: last year `=>` thì QKĐ đối với tobe

$\text{(+) S + was/were + ...}$

`16.` went

Giải thích: three days ago `=>` thì QTĐ

$\text{(+) S + Ved/V2 + ...}$

`17.` visited

Giải thích: last Sunday `=>` thì QKĐ

$\text{(+) S + Ved/V2 + ...}$

`18.` didn't go

Giải thích: yesterday `=>` thì QKĐ

$\text{(-) S + didn't + V-bare + ...}$

`19.` was

Giải thích: in 1980 `=>` thì QKĐ

$\text{(+) S + was/were + ...}$

$chucbanhoctot$
$#thaonguyeneakar$