Meaning of AGO in English

AGO

a ‧ go S1 W1 /əˈɡəʊ $ əˈɡoʊ/ BrE AmE adverb

[ Date: 1400-1500 ; Origin: From the past participle of ago 'to pass away' (11-17 centuries) , from Old English agan , from gan 'to go' ]

used to show how far back in the past something happened

5 minutes/an hour/20 years etc ago

Her husband died 14 years ago.

long ago/a long time ago

He should have finished at university long ago, but he kept taking extra courses.

a minute/moment ago

The little girl you saw a moment ago was my niece.

a little/short while ago

Tom got a letter from him just a little while ago.

They moved to a new house some time ago (=a fairly long time ago) .

We had our bicentenary celebrations not that long ago.

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GRAMMAR

ago, before, previously

Use ago to say how much time has passed from the time something happened to the present time:

We went to Madrid two years ago.

Use before to say how much time passed from the time something happened to a time in the past:

Her husband had died many years before.

Previously is used in the same way, but is more formal:

The meeting was a follow-up to one that had been held four days previously.

► Use the past tense, not the present perfect, with ago :

I started (NOT I've started) a new job a few weeks ago.

► Do not use a preposition ('at', 'in', 'on' etc) before a phrase with ago :

They first met fifteen years ago (NOT at/in fifteen years ago).

► Do not use 'since' or 'before' with ago :

I came to the US two months ago (NOT since/before two months ago).

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.