Zero Conditional

Describes situations which are always true.

If I eat organic vegetables, I feel better.

If there is too much rain, the crops are destroyed.

First Conditional

Describes a possible situation in the future.

If the virus spreads, it will expose the population to another deadly disease.

Second Conditional

Describes an unlikely or imaginary situation in the present or future.

I would exercise more if I had more time.

Third Conditional

Describes an imaginary situation in the past (something that had a chance of happening, but didn’t).

If there had been more information, people would have started eating organic foods a long time ago.

First Conditional with should

We can add should to First Conditional sentences to refer to a realistic but hypothetical situation in the future.

It sounds a little more tentative/less certain and the effect is often more literary/formal.

If these trends continue, there may be major consequences for our health.

If these trends should continue, there may be major consequences for our health. (more tentative/formal)

Second Conditional with were to

We can add were to to Second Conditional sentences to refer to an unreal, hypothetical situation in the present/future.

It sounds a little more tentative/less probable and the effect is often more literary/formal.

If you consumed a lot of protein, you would gain weight.

If you were to consume a lot of protein, you would gain weight. (more tentative/formal)

We can use inversion with three types of conditionals.

As with other examples of inversion, we tend to use it in rather formal, literary or dramatic contexts.

Conditional sentences with should

To form inversion, we replace if + subject + infinitive with should + subject + infinitive at the beginning of the clause.

If these trends should continue, there may be major consequences for our health.

Should these trends continue, there may be major consequences for our health.

Conditional sentences with were to

To form inversion, we replace if + subject + were to with were + subject + to + infinitive at the beginning of the clause.

If you were to consume a lot of protein, you would gain weight.

Were you to consume a lot of protein, you would gain weight.

Conditional sentences with had (Third Conditional)

To form inversion, we replace if + subject + Past Perfect with had + subject + Past Participle at the beginning of the clause.

If the manager had reacted faster, we might have avoided the economic crisis.

 Had the manager reacted faster, we might have avoided the economic crisis.