Perfekt med FOR och SINCE

När vi använder perfekt, kan vi definiera en tidsperiod som ägde rum innan nutid och ha dess varaktighet i åtanke, genom att använda for + en tidsenhet, eller så kan vi ha dess startpunkt i åtanke, genom att använda  since + en tidpunkt. FOR och SINCE kan båda också användas tillsammans med pluskvamperfekt. SINCE kan endast användas tillsammans med  perfekt. FOR kan även användas tillsammans med imperfekt.

For + en tidsenhet

for six years, for a week, for a month, for hours, for two hours
I have worked here for five years.

Since + en tidpunkt

since this morning, since last week, since yesterday
since I was a child, since Wednesday, since 2 o'clock
I have worked here since 1990.

Perfekt med FOR

She has lived here for twenty years.
We have taught at this school for a long time.
Alice has been married forthree months.
They have been at the hotel for a week.

Perfekt med SINCE

She has lived here since 1980.
We have taught at this school since 1965.
Alice has been married since March 2nd.
They have been at the hotel since last Tuesday.