Fist Conditional.

If she practices boxing, she will be strong.

If he doesn't study for his exam, he will flunk.
If they continue dating, they will fall in love.

Second Conditional.

If he said all that he felt , he would be my boyfriend.

If she wasn´t jealous, he would be happier.
If I arrived early, I would present my exam.

Third Conditional.

If I hadn't broken up with him, I would have had boyfriend.

If I hadn't danced with him, I wouldn´t have feel extremely happy.

If I hadn't met him, I wouldn't have known the meaning of a best friend.