When you mix blue and red, you get purple. If you mix blue and red, you get purple.
If it rains this weekend, I will stay at home and read a book.
If I could only take three things with me to a desert island, I would take a knife, a flint, and a large water bottle.
If I had been born two hundred years ago, my life would have been very different, probably involving hard manual labor and a much shorter life expectancy.
If I had woken up late this morning, I would have missed my bus and been late for school.