`1`. I am delighted to receive your letter.

`-` be+ delighted+ to V: vui sướng khi làm gì

`2`. The child is not tall enough to reach the shelf.

`-` Cấu trúc: Đủ để làm gì ( `1` chủ thể) : S+ be ( not)+ adj+ enough+ to v

`3`. He is eager to come back home at Tet.

`-` be+ eager+ to V: háo hức làm việc gì

`4`. It's very important to keep the environment clean.

`-` Cấu trúc: It+ be+ adh+ to V

`-` keep+ sth+ adj: giữ cho cái gì như thế nào

`5`. She is lucky to have a lot of good friends.

`-` be+ lucky+ to V: may mắn khi làm gì

`6`. We is very happy to live together.

`-` be+ happy+ to V: hạnh phúc khi được làm gì