Đáp án:
$1$ `:` There used to have many Citadel.
`-` Used to do sth `:` Đã từng làm gì đó
$2$ `:` She used to live on a farm.
`-` Used to do sth `:` Đã từng làm gì đó
$3$ `:` English is spoken by people in many countries.
Bị động HTĐ:
`( + )` `:` S `+` is / am / are `+` VpII `+` ( by `+` O ).
$4$ `:` I enjoy sleeping late on Sunday.
`-` Enjoy doing sth `:` Thích làm gì đó
$5$ `:` We have learnt English `7` years ago.
`-` For `+` Khoảng thời gian
Thì HTHT:
`( + )` `:` S `+` have / has `+` VpII `+` ( by `+` O ).