Using the "present perfect" we can define a period of time prior to the present moment, considering either its duration, in which case we use "for" + time period, or its beginning or starting point, in which case we use " since" + specific moment. "For" and "since" can be used with the "past perfect". "Since" supports only perfect tenses. "For" can also be used with the "simple past".
"For" + period of time
for six years, for a week, for a month, for hours, for two hours
I have worked here for five years.
"Since" + specific moment
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.
"Present perfect" with "for"
She has lived here for twenty years.
We have taught at this school for a long time.
Alice has been married for three months.
They have been at the hotel for a week.
"Present perfect" with "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.
Comentarios
Publicar un comentario