Conditionals or the ‘if clauses’ as they are commonly called are sentences (or rather a part of a sentence) which introduce a probable or hypothetical condition which is followed by a certain consequence.

For example-

  1. If you burn paper, it becomes ash.
  2. If the dog barks, the neighbours will wake up.
  3. If I were you, I would tell her the truth.
  4. If she hadn’t been busy, she would have called upon me.

In sentence 1 ‘If you burn paper’ is the condition and ‘it becomes ash’ is the result of the fulfilment of that condition. Similarly, in sentence 2 the condition ‘If the dog barks,’ leads to the certain consequence ‘the neighbours will wake up.’ However, in sentences 3 and 4 the conditions become quite less probable and the consequences as a result become less achievable.

The conditionals are, primarily, constructed using the subordinate-conjunction ‘If’. However, in certain cases other conjunctions representing ‘condition’ can also be used, such as, ‘when’ and ‘unless’.

Note:Unless is used in a sentence with negative consequence and can replace the ‘if + not’ construction.

For example-

  • Unless you stop crying, we won’t talk to you.
  • If you don’t tell me what you saw, I can’t press charges.

Or

  • Unless you tell me what you saw, I can’t press charges.

Types of Conditionals:

The conditionals are divided into four broad categories based on the decreasing order of the probability of the condition presented in the ‘if clause’. They are:

  • Zero
  • Type 1
  • Type 2
  • Type 3

Zero conditional:

The zero conditional is used to express a fact or a universal truth. The probability of the condition in the ‘if clause’ is the highest because it is factual.

Syntax- if + present simple present simple

For example-

  1. If the Earth revolves around the Sun, the seasons change.

Both the ‘if clause’ and the consequence clause have verbs in the present simple tense.

If you think about it, it is not a true form of condition because the Earth does revolve around the Sun and the seasons do change. Since, the probability is maximum in this case, the certainty of consequence is also maximum. Therefore, the ‘if’ can be replaced with ‘when’, as now it’s just a matter of time as to when the condition will take place and result in the consequence.

Let’s look at the next example to make it clearer.

  1. If you heat ice, it turns into water.

When you heat ice, it turns into water.

Since, the ice will change into water upon heating as a rule, it hardly leaves any doubts regarding the consequence. Therefore ‘if’ and ‘when’ are interchangeable in a Zero conditional.

Type 1 conditional:

Type 1 conditionals have ‘if clauses’ with highly probable present or future conditions which results in a consequence in the future.

Syntax- if + present simple future simple

For example-

  1. If it rains in the evening, I will take the bus back home.
  2. If she is here, I will speak with her.

The probability of it raining in the evening and her being here are high and so is the certainty of the consequences.

Note: the probability of the conditions in the ‘if clauses’ has nothing to do with the context. It simply means that the situation is possible.

Type 1 conditionals can also be used with imperatives and/or requests.

For example- If you see her tomorrow, ask her to call me.

Since, the probability of the condition actually getting fulfilled is high with these conditionals, the ‘if’ can be replaced with ‘when’

When you see her tomorrow, ask he to call me.(Assuming that you will definitely see her tomorrow.)

Type 2 conditional:

Type 2 conditionals represent the ‘if clause’ with conditions with very low or zero probability i.e. the conditions are hypothetical, which implies that the consequences are also not possible.

Syntax- if + past simple would be

For example-

  1. If he signed the papers, the house would be mine.
  2. If something happened, she would let me know.

In sentence 1, his signing the papers has a very low probability, and so the consequence would not take place. We can also see it the other way around. In 2, since she did not let me know, that means nothing happened.

  1. If I were you, I would tell her the truth.
  1. If she was alive, things would be different.

In sentences 3 and 4, the probability of the conditions ever coming true is zero (I am not you and she is not alive), which makes them hypothetical and so the consequences become wishful thinking.

Type 3 conditional:

Type 3 conditionals present situations that have already taken place in the past and can no longer be changed. These conditions are purely hypothetical as there is zero possibility of their occurrence. Hence, the consequences also become hypothetical.

Syntax- if + past perfect would have been

For example-

  1. If someone had counselled me as a child, I would have turned out better today.
  2. If I hadn’t challenged my fate, I would have been ruined forever.

Here, it is absolutely clear that the conditions presented in the ‘if clause’ are impossible to fulfil.

Note: Another construction of the type 3 conditional is possible by omitting the ‘if’ conjunction and beginning the clause with ‘had’.

  1. Had someone counselled me as a child, I would have turned out better today.
  1. Had I not challenged my fate, I would have been ruined forever.

Note: One can also use modal verbs ‘may/might’, ‘can/could’ in the consequence clause to heighten the uncertainty of the result. These modals can only be used with Type 1, 2, and 3 conditionals.

For example-

Type 1

If you disturb her now, she may throw you out.

If you come to my office tomorrow, I can give you the blue prints.(Present simplefuture simple)

Type 2

Couldn’t she call me if she needed my help? (Past simplewould do)

Type 3

If the other ships had answered the distress calls, Titanic might have been saved. (Past perfect would have done)