`1.` If she went to class on time, she would understand the lessons.

`2.` If she had gone to class on time, she would have understood the lessons.

`3.` If the rain hadn't been heavy, we wouldn't have cancelled the match.

`4.` Unless you know a word, you can check it in the dictionary.

`5.` Unless she comes early, she won't met her uncle.

`6.` Unless you were interested in this book, I would give you another.

`@×××××××××××@`

`-` ĐK`1` : If + S + don't/doesn't + V, S + will/can...  + V

`=` Unless + S + V(s/es) + O, S + will/can...  + V

`-` ĐK`2` : If + S + Ved/were + O, S + would/could + V

`=` Unless + S + Ved/weren't + O, S + would/could + V

`-` ĐK`3` : If + S + had + PII, S + would/could + have PII