We use conditional sentences to talk about hypotheticals (i.e. things that might happen). These sentences have two parts: a conditional clause, which usually contains a word like ‘if’, and a consequence. They also come in four main types, each expressing something different. For instance:
| Conditional Type | Usage |
| Type zero | General truths and inevitable consequences |
| Type one | Possible real-world situations and their likely results |
| Type two | Unrealistic situations and their potential results |
| Type three | Unreal past conditions and their likely results |
These conditionals are formed in different ways, so knowing how they work can help you avoid errors in your writing. As such, below, we’re going to look at how each of the conditional sentence types above is formed.
Type Zero Conditionals
We can use a type zero conditional sentence to talk about general truths and situations with inevitable consequences. In other words, we use them for conditions that always lead to a certain result.
These sentences typically take the following basic form:
If (or when) [condition] occurs, [result] happens.
Usually, they use the simple present tense for both the condition and result:
If I eat too much chocolate, I feel sick.
When it rains, the road gets wet.
The words ‘if’ and ‘when’ are interchangeable in type zero conditionals.
Type One Conditionals
We use type one conditionals for likely or plausible future situations and their consequences. This takes the standard format:
If [condition] happens, [result] will happen.
The big difference here from type zero conditionals is that the result uses the simple future tense (i.e. we use ‘will’ before the base form of a verb):
If you go to bed now, you will feel better in the morning.
The conditional clause, though, is still in the simple present tense.
Type Two Conditionals
Type two conditionals express unlikely or unreal situations and their consequences. They typically take the following form:
If [condition] happened, [result] would happen.
Here, the condition is in the simple past tense, while the result typically uses the present conditional (i.e. ‘would’ or another modal verb with a base verb), which shows that the situation is unlikely or unreal:
If I knew the answer, I would tell you.
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Note that, with this kind of conditional, you should use ‘were’ rather than ‘was’ in the conditional clause. For instance:
If I were you, I’d say no.
The ‘were’ here shows that we’re talking about a hypothetical scenario.
Type Three Conditionals
Type three conditionals express an unreal past condition and its likely results had it occurred. The basic form is:
If [condition] had happened, [result] would have happened.
We use the past perfect tense for the conditional (i.e. we use ‘had’ before a past participle) in this case, while the result is usually in the perfect conditional form (i.e. ‘would have’ and a past participle):
If Jim had got up earlier, he would have been on time for work.
We use this type of conditional when something hasn’t happened in reality. The sentence above, for example, tells us that Jim did not get up early.
Mixed Type Conditionals
A mixed type conditional is one in which the conditional clause and main clause happen in different times. For example:
If we had asked for directions, we would be there now.
Here, the conditional clause (If we had asked for directions) is in the past perfect, while the result (we would be there now) is in the simple present conditional tense. It is therefore a mix of type three and type two above.
Mixed conditionals like this are quite common, so it’s important to pay attention to the tense of each clause when writing conditional sentences!
Variations in Conditional Sentences
We’ve outlined some basic conditional sentence forms above. However, there is plenty of room for variation here, such as changing the order of clauses, forming negative conditionals, and using words other than ‘if’ in the conditional clause. You can see examples of these below:
I feel sick if I eat too much chocolate.
If you don’t go to bed now, you will feel tired in the morning.
Were I in your position, I would apologise.
As this shows, conditional sentences can be complex! So, if you’d like any help to check your writing to make sure you’re using conditionals correctly, why not submit a free sample document for proofreading?