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English definition of “if”

if

conjunction (IN THAT SITUATION)    /ɪf/
A2 used to say that a particular thing can or will happen only after something else happens or becomes true : I'll pay you double if you get the work finished by Friday . We'll have the party in the garden if the weather's good. If not (= if the weather is not good), it'll have to be inside. If anyone calls , just say I'll be back in the office at four o'clock. If she hadn't called, I wouldn't have known . I wouldn't work for them ( even ) if they paid me twice my current salary . We'll deal with that problem if and when it arises . If disturbed , the bird may abandon the nest , leaving the chicks to die .Connecting words which express a condition although : They're great kids , even if they can be demanding .literary It was a hot , if windy day .Connecting words which express a contrast B1 every time : If water is heated to 100°C it turns to steam . If I don't get enough sleep I get a headache .Connecting words which express a condition used to mean 'if it is true that': I'm very sorry if I've offended you.Connecting words which express a condition Grammar:Should you (Should with inversion)In formal situations, we can use should + subject (s) + verb (v) instead of if:Grammar:Had you (Had with inversion)In formal situations, we can use had + subject + verb instead of if in third conditional sentences:Grammar:+ In formal situations, we can use if + were to when we talk about things that might happen but which we think are unlikely:Grammar:As long as, so long as, providing, etc.Sometimes we need to impose specific conditions or set limits on a situation. In these cases, conditional clauses can begin with phrases such as as long as, so long as, only if, on condition that, providing (that), provided (that).Grammar:Or and otherwiseWe often use or and otherwise with conditional meanings:Grammar:SupposingSupposing may be used with a conditional meaning. It can be used in first, second or third conditional sentences. The speaker invites the listener to imagine a situation:Grammar:Conditionals: typical errorsGrammar:ConditionalsGrammar:Conditionals: imagined situationsConditional sentences consider imagined or uncertain situations and the possible results of these situations. The most common types of conditional sentences involve if:Grammar:Conditional sentencesConditional sentences consist of a conditional clause and a main clause:Grammar:Order of clausesConditional clauses usually come before main clauses but they may also come after them:Grammar:Verb forms in the conditional clauseThe verb in the conditional clause may be in the simple form or the continuous form, depending on the meaning:Grammar:Conditionals: ifGrammar:Imagined conditionsThere are different types of conditions. Some are possible or likely, others are unlikely, and others are impossible:Grammar:Imagined conditions: the first conditionalWe use the first conditional to talk about the result of an imagined future situation, when we believe the imagined situation is quite likely:Grammar:Imagined conditions: the second conditionalWe use the second conditional to talk about the possible result of an imagined situation in the present or future. We say what the conditions must be for the present or future situation to be different.Grammar:First and second conditional comparedWhen we use the first conditional, we think the imagined situation is more likely to happen than when we use the second conditional.Grammar:Imagined conditions: the third conditionalWe use the third conditional when we imagine a different past, where something did or did not happen, and we imagine a different result:Grammar:Real conditionalsSome conditions seem more real to us than others. Real conditionals refer to things that are true, that have happened, or are very likely to happen:Grammar:Types of conditional: summaryThe table shows how the main types of conditionals relate to one another.Grammar:If + shouldWe can use if with should to refer to events which might happen by chance or by accident:Grammar:Conditional clauses with will or wouldWill and would can be used in conditional clauses, either with the meaning of ‘being willing to do something’, or to refer to later results:Grammar:Mixed conditionalsOften, things that did or did not happen in the past have results which continue or are still important in the present. We can emphasise this by using if with a past perfect verb, and would in the main clause.Grammar:Conditionals in speakingGrammar:Conditionals: other expressions (unless, should, as long as)Grammar:UnlessConditional clauses can begin with unless. Unless means something similar to ‘if … not’ or ‘except if’.Grammar:IfIf is a conjunction.Grammar: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:Grammar: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:Grammar:If possible, if necessaryWe can sometimes leave words out after if to form fixed expressions:Grammar:If so, if notWe use so or not after if when it is obvious what we are referring to:Grammar:Even ifWe can use even if to mean if when talking about surprising or extreme situations:Grammar:If: reporting questionsWe use if to introduce reported yes-no questions and questions with or.Grammar: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:Grammar: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.
(Definition of if conjunction (IN THAT SITUATION) from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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