- if is part of the Basic English 850.
- used in a condition
- when something will cause something else
- when a condition is not true
- I'd prefer it if you took your shoes off.
- He was a great friend, if a little strange.
- When ... occurs (a programming statement).
- If A, then B, else C.
- If is used to report questions and things that are unknown.
- She asked if they had arrived yet.
- I don't know if I want to go or not.