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English definition of “if”

if

conjunction (WHETHER)    /ɪf/
B1 used to introduce a clause, often in indirect speech, that shows two or more possibilities: Mrs Kramer called half an hour ago to ask if her cake was ready. I don't care if he likes it or not - I'm coming! I was wondering if you'd like to come to the cinema with me this evening? → Compare whetherConnecting words which express a condition whetherGrammar:IfIf is a conjunction.See moreGrammar:Whether not ifWe use whether and not if after prepositions:See moreGrammar:I doubt if, I don’t know whetherWe use if or whether to introduce clauses after verbs of doubting:See moreGrammar:If, whether: typical errors[talking about a trip to Australia for a year]See moreGrammar:If or when?We use if to introduce a possible or unreal situation or condition. We use when to refer to the time of a future situation or condition that we are certain of:See moreGrammar:If: conditionsWe often use if to introduce possible or impossible situations or conditions and their results. The situations or conditions can be real, imagined or uncertain:See moreGrammar:If possible, if necessaryWe can sometimes leave words out after if to form fixed expressions:See moreGrammar:If so, if notWe use so or not after if when it is obvious what we are referring to:See moreGrammar:Even ifWe can use even if to mean if when talking about surprising or extreme situations:See moreGrammar:If: reporting questionsWe use if to introduce reported yes-no questions and questions with or.See moreGrammar:If and politenessIn speaking, we often use if to introduce a polite request. If is usually followed by modal verbs will, would, can or could when it is used to be polite:See moreGrammar:If or whether?See moreGrammar:If and whether: indirect questionsWe can use if or whether to report indirect yes-no questions and questions with or. If is more common than whether:See moreGrammar:When or if?We use when to refer to a future situation or condition that we are certain of, whereas we use if to introduce a possible or unreal situation.See more
(Definition of if conjunction (WHETHER) from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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