Conditional clauses in English can be classified into 4 types

• ZERO TYPE:   Eg. If I have time, I visit you tonight.

• TYPE I:   Eg. If she studies hard, she will pass the exam.

• TYPE II:   Eg. If you worked hard, you would finish this week.

• TYPE III:   Eg. If I had known that, I would have helped in a way.

Sentences within a condition may change position

Example: If you study hard, you'll pass the exam.

               You'll pass the exam if you study hard.