Qúa khứ hoàn thành (PAST PERFECT TENSE):

(+) S + had + VpII

(-) S + hadn’t + VpII

(?) Had + S + VpII ?

Qúa khứ tiếp diễn (PAST CONTINUOUS):

(+) S + was/were + V-ing + O

(-) S + was/were + not + V-ing +O

(?) (Từ để hỏi) + was/were + S + V-ing + O?

$\text{Công thức thì QKHT}$

$\text{(+) S+had+VPII+...}$

$\text{(-)  S+hadn't+VPII+...}$

$\text{(?) ....had+S+VPII+...?}$
$\text{Công thức thì QKTD}$

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

$\text{(-)  S+was/were+not+V_ing+...}$

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

$\text{CHÚC BẠN HỌC TỐT!!}$