You're hanging out with a group of friends late at night. You want to ask a silly question to start a discussion.
If you could live in any period in history, which one would it be?
conditionals, history, hypothetical, if 
You're about to watch a basketball game on TV. There's a show before the game where the sports announcers discuss the game. They're talking about one of the players who suffered a knee injury last year. One of them says:
The question is whether his leg is fully recovered.
You're at a job interview and have been asked to described one of your weaknesses. You have to answer, but you want your answer to make you sound impressive. You want it to sound like this weakness is not really a problem. So you say:
If I HAD to pick something, I'd say it's that I have trouble saying "no" to people's requests.
You chose not to move to Hollywood to follow your dream of being an actor. Your friend asks you many years later:
Do you ever think "what if"?
You hear a commercial for chocolate chip cookies. It says:
If you like chocolate, you'll love Tollhouse double chocolate chip cookies.
This structure is often used in advertisements to tie the product that's being sold to something else that the customers already like.
commercial, food, if You were planning to send an email to some friends inviting them to go out for dinner. Now you're not sure if you sent it. You say:
I can't remember if I sent it or not.
if, invitation, memory, whether You're being asked what color shirt a person was wearing. You think it was blue, but you're not 100% sure. You say:
If I recall correctly, I think it was blue.
clothing, conditionals, if, memory, uncertainty 