If, Provided, Unless and As Long As

You probably already know that ‘if’ is a common feature of conditional statements. For example:

i) If it rains I’ll get wet.
ii) If I won the lottery I’d travel around the world.

However, it is also possible to use words like ‘provided’, ‘as long as’ or ‘unless’ in conditional structures, each with their own meaning.
(If you need practice in Conditionals, see our lesson ‘Conditionals for Real and Unreal Situations‘.

Uses

a) ‘Provided’ or ‘as long as’ have a similar meaning and are used when we want to emphasise the condition. For example:

i) Provided you pay me back soon (condition), I will lend you the money.
ii) My teacher thinks I will pass the exam, provided I continue to work hard (condition).
iii) As long as our governments stay firm (condition), we will get global warming under control.
iv) I think I’ll continue studying English, as long as I have the time to do so (condition).

“If’ could also be used in all these examples above.

b) We use ‘unless’ when it has the meaning ‘except if’. “Except if’ means that ‘x’ is generally true apart from when ‘y’ happens. For example:

i) I won’t be able to go on holiday this year, unless I can earn more money.
ii) I’ll be able to travel home this weekend, unless the train strike continues.

In the first example above, the speaker doesn’t expect to be able to go on holiday.
In the second example, the speaker is optimistic that he/she will be able to go home.

Need more help?

Watch this video for an explanation of how to use ‘unless’.

Over to you

Match the beginning of a sentence with the correct ending. Then complete the sentences using ‘if’, ‘provided’ or ‘unless’. For example:

You can borrow the car provided you fill it with petrol.

Beginnings

you/borrow/the car
you/not do as you are told
I/not help you with your homework
I/cook the dinner
I won the lottery
temperature rise

Endings

the ice/melt
you fill it/petrol
you/not get a treat
buy/new car
you wash up
you promise to concentrate