`2.` meet (Câu điều kiện loại 1)
`3.` must be finished (Bị động với ĐTKT: must be Vpp)
`4.` were playing (Thì quá khứ tiếp diễn)
`5.` have been (HTHT + since + QKĐ)
`6.` had been - came (QKHT + before + QKĐ)
`7.` This tree has to be cut down before the raining season. (Bị động: have/has to be Vpp)
`8.` The ceilings fans weren't turned off last night. (Bị động QKĐ: was/were Vpp)
`9.` The Internet has been used to get the news (by many people). (Bị động HTHT: have/has been Vpp)
`10 + 11.` Đúng.
`12.` She asked me if I was hungry (Câu tường thuật lùi thì: HTĐ `->` QKĐ)
`13 + 14 + 15.` Đúng.
@ `Ly`