for long
prep. phr..prep. phr.. for a long period of time. You usually use this in questions or negative sentences.
prep. phr.. an adverbial prepositional phrase indicating duration; primarily restricted to negative and interrogative contexts in standard usage.
I won't be gone for long.
Have you been waiting for long, or did you just arrive?
The peace treaty did not hold for long, as border disputes resurfaced within a few months of the signing.
typically follows a verb and is most common in negative statements or questions.
contrast with 'for a long time'; 'for long' is more common in negative/interrogative structures, whereas 'for a long time' is preferred in affirmative statements.
I lived there for long.I lived there for a long time.in positive statements, 'for a long time' is the standard choice; 'for long' sounds unnatural here.