Настоящее совершенное время с FOR и SINCE

При употреблении настоящего совершенного времени мы можем определить предшествующий период времени с учётом его продолжительности, с for + период времени, или с учётом начало отсчёта, с since + момент времени. FOR и SINCE могут также использоваться с прошедшим совершенным временем. SINCE может быть использован только с совершенными временами. FOR может быть использован ещё и с простым прошедшим временем.

For + период времени

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

Since + момент во времени

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.

Настоящее совершенное время с 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.

Настоящее совершенное время с 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.