if you saw some boys bullying your mate, you would call the teacher. / if you had seen some boys bullying your mate, you would have called the teacher.
if he had paid more attention, he wouldn't have lost his credit card last week.
if there is no air, wood doesn't burn.
if you ask him politely, he will tell you.
i am glad we had a map. what would we have done if we hadn't had it?
smartphones will be lighter and lighter if they continue to evolve so quickly.
he wouldn't have been here on time if he had been stuck in a traffic jam.
i wouldn't know what is happening in the world if i didn't read the papers every day.
will your parents be happy if you get a good mark? / would your parents be happy if you got a good mark?
the accident was your fault. if you had driven more carefully, it wouldn't have happened.