Past simple

1)My friends were at the party yesterday.

2)His sister was at our office the day before yesterday.

3)We were at the party two daysago.

 Present Perfect

1)They have already checked a file.

2)I havejust translated it.

3)I have never been to london.

Past simple:

I went to Paris in 1987

I saw the President last summer

His sister  hasn"t finished school yet

Present Perfect:

I have been to Paris already

(And I can tell about the city)

I have never seen the Pyramids

(And I would like to see the place)