`->` It was such a difficult test that we couldn't do.
`->` The test was so difficult that we couldn't do it.
- Cấu trúc "so...that" (với động từ tobe): quá đến nỗi mà...
S + tobe + SO + adj + that + S + V.
- Cấu trúc "such...that" (với động từ tobe)
S + tobe + such + adj + noun + that + S + V