`31.` English can be spoken at the conference.

`->` Bị động `-` ĐTKT: S + ĐTKT + be + P2 + (by O)

`32.` She has played the piano for `5` years.

`->` S + began + to V + time + ago

`=` S + have/has + P2 + for + time

`33.` Answering that question is difficult for me.

`->` V-ing đứng đầu câu với chức năng chủ ngữ

`->` be + adj + for sb: thật...cho ai...

`34.` The teacher lets students answer the question.

`->` let sb do sth: cho phép ai làm gì

`31.` English can be spoken at the conference.

`-` Câu bị động: ĐTKT "can": S + can + be + V3/ed + (by O)

`->` Có thể được làm gì

`32.` She has played/ has been playing the piano for 5 years.

`-` S + started/ began + V-ing/ to V + time + ago

`->` S + have/has + V3/ed + for + khoảng thời gian `/` S + have/has + been + V-ing + for + khoảng thời gian

`33.` Answering that question is difficult for me.

`-` It + tobe + adj + (for sb) + to V

`->` V-ing + tobe + adj + (for sb)

`34.` The teacher lets students answer the question.

`-` permit sb to do sth = let sb do sth: cho phép ai đó làm gì

`-` Thì HTĐ: `(+)` S + V(s/es)

`-` Vì "The teacher" là S số ít `->` V phải thêm "s/es"