a long time ago
fixed phr..fixed phr.. This means something happened many years or centuries in the past.
fixed phr.. An adverbial phrase of time indicating a point in the distant past, typically used with the simple past tense.
Dinosaurs lived a long time ago.
He moved to this city a long time ago, when he was just a boy.
Though now a bustling metropolis, this city was just a small, quiet fishing village a long time ago.
This phrase is usually placed at the beginning or end of a sentence.
Point out that 'ago' requires a past tense verb, as it refers to a finished time, unlike 'for' or 'since' which are often used with perfect tenses.
I have visited Paris a long time ago.I visited Paris a long time ago.Use the simple past tense with 'ago' because it refers to a specific, finished time in the past.