Any sentence which can be stated or formatted with IF Clause is a conditional where the truth of the sentence depends upon main clause being true when the condition clause is true. These are of 5 types namely Zero, 1st, 2nd, 3rd and Mixed. Zero Conditional applies to current or continuous time with a real and possible scenario. The zero (0) conditional is the factual conditional. It is used to talk about habits, scientific facts, general truths, laws of nature, instructions. Such conditions cannot be manipulated, controlled, planned, nor be a matter of uncertainty or possibility. This is the reason why its named zero conditional. The word when or whenever which mean any time/every time, can often replace the word ‘if’ in the Zero Conditional without changing the meaning.
Examples:
If (or When or Whenever) food is cooked on low heat, it tastes better. [general fact]
Whenever anyone parks car there, traffic police tows away the car. [general fact]
*Birds chirp when sun rises. [natural phenomenon]
Water boils if you heat it. [scientific fact]
If I drink, I never drive. [habitual behaviour]
Dial 9, if you want to speak to reception. [a general – where independent clause is imperative; the instruction must be general and not specific to any person, situation or time etc.]
I can’t read if I don’t wear glasses. I can’t read unless I wear glasses. [general fact]
If one is above 60, one must take supplements.
It is easier to meditate when I am listening to the chant.
I can work till late night if I have siesta for just half an hour in the afternoon.
The baby sleeps for long hours if she has been fed full stomach.
(*)When can mean ‘at the time’, or ‘anytime’. ‘If’ and ‘when’ can be used interchangeably to convey the meaning ‘anytime’ but not ‘at the time’. ‘If’ being a conditional, by default means that ‘any time the condition is fulfilled’ which also means the condition can arise anytime. Hence it is incorrect to write ‘Birds chirp if sun rises.’ ‘Leaves fall when (if) it is autumn’; Sun cannot arise anytime and autumn doesn’t arrive any time.
Note: In case of zero conditional, tenses of both dependent ‘if – clause’ and independent clause are mostly simple present. However tense of dependent ‘if-clause’ can also be present perfect, present continuous, and independent clause can take modals like can, could, should, and must.
Zero conditional can also be used for past tense in place of ‘used to’ and ‘would’.
Whenever four of us had leisure time, we played (used to play/ would play) board game.
In spite of both the clauses being in the present tense, the sentence need not be zero conditional as elucidated with the example below.
a) If anyone calls, tell that I am in a meeting.
b) If anyone calls, you will tell that I am in a meeting.
c) Whenever anyone calls, tell that I am in a meeting.
Sentence (a) and (b) have the same meaning which is different from that of sentence (c). Thus, to test if a sentence is zero conditional, replace ‘if’ with when/whenever/any time / every time, and check if the meaning remains same or changes. Second test is to use the verb in independent clause in future tense. Such sentences which do not mean same with replacement of ‘if’ with ‘when/whenever’ and which can take or takes the auxiliary verb ‘will’ are known as ‘1st Conditionals’.
Type 1 Conditional is the possible/probable conditional. It is used to talk about possible future events and their likely results. You can use the first conditional to talk about predictions, superstitions, future plans, warnings & threats, and offers & suggestions. These are things that are real, so this conditional is also called the future real conditional. Unlike zero conditional where it is irrelevant, in case of 1st conditional the choice of exercise/control or possibility of occurrence of the conditional part of the sentence is not absolute or certain. The result is however real and certain (according to the speaker) just as it is in case of zero conditional.
In the sentence of zero conditional, ‘if you heat water, it boils’, issue is not about whether you will actually heat water or not or whether you are likely to heat water or not. This question about possibility of heating water is irrelevant to the proposition.
The dependent “if” clause in 1st conditional includes the simple present tense, and the main clause uses the simple future.
Examples:
If you spend most of your money now, you will not have enough left for shopping in the other mall. [prediction]
If (or When) the water rises 1 ft above the danger mark, village will be flooded. [prediction]
If you return his money, he will return your car. [prediction]
If a cat crosses your path, you will be unlucky. [superstition but true according to the speaker]
If you get an extra ticket, I will give you company. [future plan/promise]
If you park your car there, it will be towed away. [warning]
If you are late again, you will get a notice. [threat]
If you don’t leave right now I am going to call the police. [‘going to’ can be used in place of ‘will’]
If you plan to vacate on weekend, I might be able to help with packing.[use of ‘might’ instead of ‘will’ is allowed] Note: It is important to note that ‘might’ denotes chance or probability but it doesn’t denote falsity. Whatever is the probability be it 50% or more or less, that probability is true. Use of modals such as ‘can’ and ‘should’ are used for offer and suggestion.
I can get you a VIP seat if you are interested.
If you are passing by that road, you should/must take a small detour to visit that 11th century temple to marvel at its magnificent architecture.
Remember to buy some fruits if you go (are going) to the market. [imperative]
If anyone calls, tell that I am in a meeting. [imperative]
Use of unless (if...not), so long as, provided, in case, supposing, in the event (that/of) instead of ‘If’, have the same meaning for sentences in 1st Conditional. However there are subtle differences with ‘if’ as explained in the examples below.
Supposing = in the uncertain event of, in the doubtful case that, assuming that, hoping that
Provided = if it is certain that, under the condition that, if it is ensured that, only if, in the case that, depending on whether
In case = in the unlikely event of
In case (supposing, provided) more people turn up, we can use our neighbour’s house which is currently vacant.
You can take my car provided (supposing, in case) you return it tomorrow with full tank.
I would love to accompany you next weekend supposing (provided, in case) I am not assigned any emergency duty (which I am not very certain of).
I would love to accompany you next weekend in case (provided, supposing) I am not assigned any emergency duty (and it is unlikely that I would get any emergency call).
‘Just in case’ unlike ‘in case’ cannot be used as a replacement for ‘if’. ‘Just in case’ = ‘because of the possibility that’ denoting contingency.
Take an umbrella just in case it rains = Take an umbrella because of the possibility that it might rain. It is however wrong to write ‘Take an umbrella if it rains’ which means ‘unless it is raining do not take umbrella’
Here is my phone number just in case we get separated.
Call me in case/if we get separated.
Sometimes ‘just in case’ is written as ‘in case’ in short but one must be treated as ‘’just in case’ for the meaning. ‘If’ denotes possible cause/ condition for future outcome, whereas ‘just in case’ denotes future possibility as cause for present action.
Adverbs of time like ‘when, after, before, until, as soon as’ are used to denote what is ‘definite’ or ‘for sure’ without any conditionality of probability/possibility as it is in case of ‘if’.
If the meeting gets cancelled, I will inform you. [1st Conditional]
When the meeting gets over, I will inform you.
Even if (Whether or not/ Irrespective of whether... or not) includes both the propositions of ‘if’ and ‘if..not’
If you do not return his money, he will not return your car but if you return his money he will still not return the car = Even if you (Irrespective of whether you) return his money (or not), he won’t return your car.
If return his money, he will return your car but if you do not return his money he will still return the car = Even if you don’t return his money, he will return your car.
Even if I don’t (Whether or not I) get scholarship, I will still ( ) go abroad for higher studies. = If I get scholarship I will go abroad for higher studies but If I don’t get scholarship, I will still go...
It may worth noting that unlike EVEN IF, EVEN THOUGH is not a conditional. ‘Even though’ means ‘In spite of’.
E.g. The machine is giving trouble even though (even if)it has been repaired twice recently.