Long is an adjective or an adverb.
We can use long to talk about time, distance or length.
We use long as an adverb in questions and negative clauses to talk about duration:
How long has Valerie been staying with you?B:
She arrived in January, so she’s been here for four months.
Marco didn’t stay long at the party.
Don’t be long.
We don’t use long on its own in affirmative clauses. We often use (for) a long time:
We waited for a long time in the rain for the bus.
They took a long time getting here.
They took long…
We can use long in affirmative clauses with too, enough and so:
A month is too long to wait for an appointment.
We’ve waited long enough for a reply. I think we need to phone them.
You took so long. What were you doing?
When we talk about actual amounts of time, we can use phrases with time + long, or phrases like all day long, all month long:
The lecture was three hours long.
We worked all day long.
We can also use a long time ago, long ago or long before to refer to a time many years in the past:
This castle was built a long time ago. (or … was built long ago.)
Long before you were born, there was a factory here. It was closed in the 1960s.
We use long as an adjective:
You’re home already. That can’t have been a very long film.
We can use the phrase a long way to talk about distance:
My house is a long way from the station. You’ll have to take a taxi.
It’s a long way to the nearest petrol station.
In negative statements and questions we usually use far:
My house is not far from the station.
Is it far to the beach?
We use long to talk about the length of something:
It was three metres long and four metres wide.
How long is the boat?
This is such a long queue. It’s going to take at least an hour.
As long as
The phrase as long as is used as a conjunction. It means ‘on condition that’:
As long as the weather is okay, we’re going to paint the house tomorrow.
Jenny said she’d come to the party as long as we don’t stay too late.
No longer and not any longer
We can use the phrases no longer and not … any longer to refer to something that used to exist or happen but does not exist or happen now:
There are no longer any family bakeries in our town.
Are you still working at the garden centre?B:
No, not any longer.
We can’t use long on its own in affirmative sentences:
Will it take long?B:
No, it won’t take long. (or Yes, it’ll take a long time.)
Yes, it’ll take long.