Present Real Conditionals 

A conditional is made up of two parts: the if-clause and the main clause. We can put either one first and it doesn't change the meaning. We usually use a comma if we put the if-clause first.  

• If it rains, we'll go to the cinema.  

‘If it rains’ is the if-clause and ‘we'll go to the cinema’ is the main clause. We can also say ‘we'll go to the cinema if it rains’ and the meaning is exactly the same.  

Although in grammar books we often learn about the zero, first, second, and third conditionals, there are also other ways to use conditionals. Here I'll explain some of the other possibilities. 

Real Conditionals  

Real conditionals are for things that are either true or likely to be true. Grammar books often talk about how we use them for general truths (this is the zero conditional) and to talk about likely things in the future (this is the first conditional). But we can also use them in other ways. The tenses in real conditionals follow the normal rules for tense and modal use.  

Present Real Conditionals 

1: Present real conditionals can be used for general truths. This is the classic zero conditional. The result, which is in the main clause, always happens if the condition, which is in the if-clause, happens. This is very common with mathematical or scientific facts. We generally use the present simple in both clauses and this makes sense - as in other kinds of sentences, we use the present simple to talk about things that are generally true.  

• If you mix oil and water, the oil floats.
• If you add two and two, you get four. 

2: Present real conditionals can be used for habits in the present or general habits. We also often use the present simple in both clauses when we're talking about habits. Whenever the thing in the if-clause happens, then the thing in the main clause follows. Again, it makes sense to use the present simple as we often use it in all kinds of sentences for present habits. 

• If my husband cooks dinner, I clean up. (This means that every time my husband cooks dinner, I clean up.)
• If John goes to London, he visits his sister. (This means that every time John goes to London, he visits his sister.) 

We can also use other verb tenses for general truths and for habits. We can use the present continuous, the present perfect or the present perfect continuous with their normal meanings in either clause and we don't need to use the same tense in both clauses. This is most common with habits.  

• If I'm travelling, I phone my children every day.  If she hasn't had her coffee, she's grumpy.  

But we can also use different present tenses even when we're talking about general truths, though it is much more common to use the present simple in both clauses.  

• If this paint has dried properly, it's waterproof. (We use ‘has dried’ to show that the drying needs to happen before the paint is waterproof.) 

We can also use modal verbs in either clause, especially ‘can’ and ‘may’.  

• If I move around, I can concentrate better. (This means every time I move around, I can concentrate better.) 

If we want to tell people how they should behave or give advice, we can use an imperative in the main clause.  

• If you discover a fire, call the fire brigade immediately. 
• If you have a headache, take some Paracetamol.  

We can also use ‘should’ to give advice.  

• If you have a headache, you should take some Paracetamol.  

3: Present real conditionals can be used to talk about specific situations in the present. These situations are not general truths or habits, but a specific thing with a result either in the present or in the future. It's common to use a modal verb in the main clause in this case. And we can use this kind of conditional when we don't know if the thing are true or not true.  

• If it's raining outside now, we can call a cab. (I don't know if it's raining or not raining.)
• If John and Amanda are on their way here now, you should start making dinner. (Again, I don't know if they're on their way here or not.) 

We can use ‘will + infinitive’ or ‘will + be + verb-ing’ when we're making a guess about the present in this kind of conditional. This use of will isn't talking about the future. Rather it's about using will to talk about something we're not certain about in the present. (See the Terrific Tenses course for more about this use of ‘will’.) 

• If Lucy's at home, she'll be reading. (This means that if Lucy's at home, I believe she is reading now but I'm not certain.)