The exercise was so difficult that the students couldnt do it. A. The exercise was so difficult for the students to do. B. The exercise was too difficult for the students to do. C. The exercise was enough difficult for the students to do. D. The exercise was too difficult for the students to do it.

`-` `A`nswer : `bbB`

`->` Be + too + adj + (for sb) + to V : Quá

`->` Be + so + adj + that + S + V : Quá `=>` `A` sai công thức 

`->` Be + adj + enough + (for sb) + to V : Đủ `=>` `C` sai công thức

`->` Khi chủ ngữ đã là vật thì sau to V không cần có O `=>` D sai

`->` Bài tập quá khó đối với học sinh.

`1. B`. The exercise was too difficult for the students to do.

`-` S + be + too + adj + for O + to-V: quá ... (cho ai) để ...