If I fail the exam, my father will punish me.
Or ( Hopefully, the opposite is true!)
If I pass the exam, my father will reward me.
(There should not be a space between the last letter in the word and the required comma and period.)
If I'd bought an expensive home, I could marry now.
If I'd bought an expensive home, I'd now be able to marry.
(This expresses the idea that if you had already bought a home, you would be in the position to marry.)
If you watch violent movies, you will become cold-hearted.
If you continue to watch violent movies, you will become cold-hearted.
(This expresses the thought that a habit or routine of watching violent movies will eventually cause you to become cold-hearted.)
Hope this helps