as long as
used in conditionals
You can use as long as or so long as to say that one thing is true only if another thing is true. For example, if you say ‘As long as you are under 16, you can take part in activities’, you mean ‘If you are under 16, you can take part in activities’.
You use a simple form after as long as and so long as.
We were all right as long as we kept quiet.
The president need not resign so long as the elections are supervised.
duration
You also use as long as to say that something lasts for a long period of time, or for as much time as possible.
Any stomach ache that persists for as long as one hour should be seen by a doctor.
I love football and I want to keep playing as long as I can.
Don't use ‘so long as’ in this way.
Be careful
Don't use ‘as long as’ when you are talking about distances. Don't say, for example, ‘I followed him as long as the bridge’. You say ‘I followed him as far as the bridge’.
Don't use ‘as long as’ when you are talking about distances. Don't say, for example, ‘I followed him as long as the bridge’. You say ‘I followed him as far as the bridge’.