`18)` We decided to take a boat trip around the floating market to experience the life of people there.

`->` S + V-qk + ...

`->` decided to V: quyết định làm gì

`19)` Nam was the last student to join the trip to Hoi An Ancient Town last week.

`->` S + was/were + N + ... (có last week)

`->` be the last to V: là người cuối làm gì

`20)` She is going to Hue this weekend to buy some bai tho conical hats.

`->` S + be + V-ing ... (dùng để chỉ HĐ đã lên kế hoạch từ trước)

`->` buy sth: mua cái gì

`-`

`@` to V-inf: để làm cái gì

@magnetic

18 We decided to take a boat trip around the floating market to experience the life of people there.

- to V : để làm gì -> Chỉ mục đích

19 Nam was the last student to join the trip to Hoi An Ancient Town last week.

- the last -> Rút gọn MĐQH với to V-inf

20 She is going to Hue this weekend to buy some bai tho conical hats.

- Tương tự câu 18