`24`. were ... have been

`⇒` Dấu hiệu: for 20 years

`⇒` thì HTHT

`⇒` Vế trước thì HTHT sẽ là thì QKĐ

`25`. arrived .... had already gone

`⇒` Cấu trúc: When + QKĐ, QKHT

`26`. is starting

`⇒` Dấu hiệu: at 9 a.m today

`⇒` thì HTTD

`27`. always criticizes

`⇒` Dấu hiệu: always

`⇒` thì HTĐ

`28`. is being used .... was invented

`⇒` Dấu hiệu: at present

`⇒` thì HTTD `→` Câu bị động: is/am/are + being + Vpp

`⇒` Dấu hiệu: in 1830

`⇒` thì QKĐ `→` Câu bị động: was/were + Vpp

`29`. has just been published

`⇒` Cấu trúc: S + have/has + been + Vpp + ( by O )

`30`. has done ... hasn't finished

`⇒` Dấu hiệu: since, yet

`⇒` thì HTHT.