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if + subject + present simple, subject + will + infinitive
真实条件句，表示很可能发生的情况。
If it rains, I will stay home.
如果下雨，我就待在家里。
如果；假如
先理解核心含义，再看它在真实句子里的用法。
如果；假如
Supposing that; used to introduce a condition that may be true or false.
If it rains, I will stay home.
如果下雨，我就待在家里。
假设,如果,在......情况下；用于引入一个可能为真或为假的条件。
Supposing that, assuming that, in the circumstances that; used to introduce a condition that may be (or prove to be) either true or false.
假设；与过去或过去完成时虚拟语气连用,表示反事实或假设条件。
Supposing that; used with past or past perfect subjunctive to indicate a counterfactual or hypothetical condition.
考虑到......；鉴于；引入一个已知为真的条件。
Considering the fact that; given that; introducing a condition that is known to be true.
当......时；每当；每次。
When; whenever; every time that.
If you heat ice, it melts.
如果你加热冰，它就会融化。
If she calls, tell her I'm busy.
如果她打电话来，告诉她我很忙。
If I had more time, I would travel.
如果我有更多时间，我就会去旅行。
真实条件句，表示很可能发生的情况。
If it rains, I will stay home.
如果下雨，我就待在家里。
与现在事实相反的虚拟语气。
If I were you, I would study harder.
如果我是你，我会更努力地学习。
与过去事实相反的虚拟语气。
If I had known, I would have come.
如果我早知道，我就来了。
if 引导宾语从句，表示“是否”，常可替换为 whether。
I wonder if he is coming.
我想知道他是否来了。
Not this
If it will rain tomorrow, we will cancel the picnic.
Use this
If it rains tomorrow, we will cancel the picnic.
在真实条件句中，if从句用一般现在时表示将来，而不用will。中文常使用'如果...会...'，导致学习者误用will。
Not this
I am not sure about if to accept the offer.
Use this
I am not sure about whether to accept the offer.
在介词后或直接跟不定式时，应该用whether而不是if。if引导名词性从句时通常不能位于介词后。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
要是…就好了；但愿
If only I had more time, I would visit you.
要是我有更多时间，我就去看你了。
如果是这样
Are you free tonight? If so, let's have dinner.
你今晚有空吗？如果是这样，我们一起吃晚饭吧。
如果不是这样；否则
We need to finish today; if not, we'll miss the deadline.
我们今天必须完成；否则就会错过截止日期。
如果可能的话
Please let me know if possible by tomorrow.
如果可能的话，请在明天之前告诉我。
如果有必要
You can call me if necessary.
如果有必要，你可以给我打电话。
如果有的话
There are few errors, if any, in the report.
报告中如果有错误的话也很少。
要是...就好了
If only I had studied harder.
要是我当时更努力学习就好了。
如果有什么不同的话
The weather isn't getting better; if anything, it's getting worse.
天气没有好转；如果有什么不同的话，那就是变得更糟了。
如果，一旦
We will discuss that if and when it becomes necessary.
如果有必要，我们会讨论那件事。
如果你建造它，他就会来。
If it rains, we will stay home.
如果下雨，我们就待在家里。
如果你受不了热，就离开厨房。
If you are tired, you should rest.
如果你累了，就应该休息。
Use if naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
把'if'想成一把锁，‘如果’有钥匙就能打开。
neutral
All words ending with -iff rhyme with /ɪf/. Beware that 'off' (/ɒf/) looks similar but sounds different.
Dictionary facts from AI_FALLBACK, DICTIONARY_API_DEV, ECDICT, WIKTIONARY.