Conditionals – Alternatives to If

Unless

We can use ‘unless’ as an alternative to ‘If…not’.

I’ll be home at eight, if I don’t have to work late.

I’ll be home at eight, unless I have to work late.

We can also use ‘unless’ to mean ‘only if there’s no other option’.

Only disturb me if it’s really urgent.

Don’t disturb me unless it’s really urgent.

As long as, so long as, on the condition that, providing (that), provided (that)

We can use as long as, so long as, on the condition that, providing that and provided that as an alternative to ‘if’. ‘On the condition that’ is more formal than the other expressions.

We use these words to say a condition must happen to achieve a specific result. It is similar to saying ‘only if’.

I’ll only lend you the money if you promise to repay me.

As long as you promise to repay me, I’ll lend you the money.

Susanna said she would come provided (that) she could get the time off work.

Whether

When there is a choice of two possibilities, we normally use whether:

Let me know whether you can come or not.

In indirect speech, we can use if or whether to introduce reported yes/no questions:

Do you have any free time on Sunday? - I’m not sure if I’ll have any free time on Sunday.

Are you coming on Sunday? I don’t know whether I’ll have any free time on Sunday.

Click on these links to learn more about the Conditionals