Frequency: The word is one of the 700 most common words in English.
1.
You use if in conditional sentences to introduce the circumstances in which an event or situation might happen, might be happening, or might have happened.
She gets very upset if I exclude her from anything...
You can go if you want...
If you went into town, you'd notice all the pubs have loud jukeboxes...
Do you have a knack for coming up with ideas. If so, we would love to hear from you.
CONJ
2.
You use if in indirect questions where the answer is either 'yes' or 'no'.
He asked if I had left with you, and I said no...
I wonder if I might have a word with Mr Abbot?
= whether
CONJ
3.
You use if to suggest that something might be slightly different from what you are stating in the main part of the sentence, for example that there might be slightly more or less of a particular quality.
Sometimes, that standard is quite difficult, if not impossible, to achieve...
I'm working on my fitness and I will be ready in a couple of weeks, if not sooner...
CONJ: with neg
4.
You use if, usually with 'can', 'could', 'may', or 'might', at a point in a conversation when you are politely trying to make a point, change the subject, or interrupt another speaker.
If I could just make another small point about the weightlifters in the Olympics...
CONJ
5.
You use if at or near the beginning of a clause when politely asking someone to do something.
I wonder if you'd be kind enough to give us some information, please?...
CONJ [politeness]
6.
You use if not in front of a word or phrase to indicate that your statement does not apply to that word or phrase, but to something closely related to it that you also mention.
She understood his meaning, if not his words, and took his advice.
PHRASE
7.
You use if to introduce a subordinate clause in which you admit a fact which you regard as less important than the statement in the main clause.
If there was any disappointment it was probably temporary...
CONJ
8.
You use if ever with past tenses when you are introducing a description of a person or thing, to emphasize how appropriate it is.
I became a distraught, worried mother, a useless role if ever there was one...
PHRASE [emphasis]
9.
You use if only with past tenses to introduce what you think is a fairly good reason for doing something, although you realize it may not be a very good one.
She writes me often, if only to scold me because I haven't written to her...
PHRASE
10.
You use if only to express a wish or desire, especially one that cannot be fulfilled.
If only you had told me that some time ago...
PHRASE [feelings]
11.
You use as if when you are making a judgment about something that you see or notice. Your belief or impression might be correct, or it might be wrong.
The whole room looks as if it has been lovingly put together over the years...
PHRASE
12.
You use as if to describe something or someone by comparing them with another thing or person.
He points two fingers at his head, as if he were holding a gun...
PHRASE
13.
You use as if to emphasize that something is not true. (SPOKEN)
Getting my work done! My God! As if it mattered.
PHRASE [emphasis]
14.
You use 'if anything' to introduce something which strengthens or changes the meaning of the statement you have just made, but only in a small or unimportant way.
Living together didn't harm our friendship. If anything it strengthened it...
PHRASE: PHR with cl
15.
You use 'It's not as if' to introduce a statement which, if it were true, might explain something puzzling, although in fact it is not true.
I am surprised by the fuss she's making. It's not as if my personality has changed.
PHRASE: V inflects
16.
You say 'if I were you' to someone when you are giving them advice.
If I were you, Mrs Gretchen, I just wouldn't worry about it...
PHRASE: PHR with cl