`1`. is looking

`⇒` Trước nó là câu mệnh lệnh

`⇒` thì HTTD

`2`. has learnt

`⇒` Dấu hiệu: for three years

`⇒` thì HTHT

`3`. have you known. ... have known

`⇒` Dấu hiệu: for 5 years

`⇒` thì HTHT

`4`. Has she fed

`⇒` Dấu hiệu: yet

`⇒` thì HTHT

`5`. haven't seen... were

`⇒` Dấu hiệu: since

`⇒` thì HTHT

`⇒` Cấu trúc: Sau since là QKĐ

`6`. Has she finished

`⇒` Dấu hiệu: yet

`⇒` thì HTHT

`7`. Has your dog ever bitten.... bit

`⇒` Dấu hiệu: ever `⇒` thì HTHT

`⇒` Dấu hiệu: last month `⇒` thì QKĐ

`8`. have jut made

`⇒` Dấu hiệu: just

`⇒` thì HTHT

`9`. Have you ever been

`⇒` Dấu hiệu: ever

`⇒` thì HTHT

`10`. started

`⇒` Dấu hiệu: last Sunday

`⇒` thì QKĐ