$1$. Was walking
$2$. Were having
$3$. Was sitting
$4$. Was talking
$5$. Were driving
$6$. Was riding
$7$. Was raining
$8$. Were singing
$9$. Was walking
$10$. Was going
Cấu trúc thì quá khứ tiếp diễn:
$(+)$ S + was/were + V-ing.
$(-)$ S + was/ were + not + V-ing.
$(?)$ Was/ were + S + V-ing?