in this café between 1905 and 1910.
Note that some time expressions (e.g. this morning, recently and lately) may refer to either a completed or an incomplete period of time depending on the context and whether or not the time of speaking is included in the given period:
I
have seen
him this morning.
(it is still morning)
I
saw
him this morning.
(it is later during the day)
He
has put on
some weight recently.
(in the past few days/weeks/months etc.)
He
put on
some weight recently.
(some time ago)
Reference to an incomplete period of time, however, does not always involve the use of the present perfect tense:
Have
you
been
to Lake Balaton
this year
?
(any time this year)
Did
you
go
to Lake Balaton
this year
?
(at the time when you go there every year)
Although both actions are related to an incomplete period, the present perfect in the first sentence refers to an indefinite time; meanwhile, the past simple in the second sentence implies a definite time (supposing the recipient of the question always visits Lake Balaton at the same time every year).
Quotes:
I have never met a man so ignorant that I couldn't learn something from him. - Galileo Galilei
Present perfect with FOR and SINCE
The question words how long? and since when?, and the prepositions for and since are used with the present perfect tense to express that something started in the past and is still true. How long? and for refer to an incomplete period of time, while since when? and since refer to a point in time:
I
have lived
here
for two months
.
I
have lived
here
since January
.
"
How long have
you
known
José?" "For ten years."
"
Since when have
you
known
José?" "Since the early 1990s."
The point in time after since can also be expressed with a clause containing a verb in the past simple:
I have lived here
since I was born
.
I've known José
since we were young
.
Related topics:
IT'S (BEEN) + DAYS / WEEKS / MONTHS / etc. + SINCE
Present perfect continuous with FOR and SINCE
Past simple to express a point in the past
Past simple for actions happening over a period of time in the past
Past perfect with FOR
Future perfect with FOR
Present perfect with JUST
The present perfect tense is used for recently completed actions, usually with the word just:
I
have just started
a typing course.
If the exact time is mentioned, the past simple is used:
I
started
a typing course
a few weeks ago
.
Just now also requires the past simple tense and means "a moment ago":
I
spoke
to him
just now
. He says hi.
Present perfect with YET and ALREADY
The time expressions yet and already are often used with the present perfect tense. Yet is used in negative and interrogative sentences:
I
haven't finished yet
.
Have
you
talked
to him
yet
?
Already is usually used in affirmative sentences:
I'
ve already told
you more than I should.
IT'S (BEEN) + DAYS / WEEKS / MONTHS / etc. + SINCE
The structure it's (been) + days / weeks / months / etc. + since is used to emphasise the length of time that has passed since a past event:
It's been weeks since
his last blog post.
It's been a long time since
I met him.
How long has it been since
they moved away?
In the sentences above, it's been stands for it has been (present perfect); however, in everyday speech, it is more common to use the present simple instead of the present perfect:
It's weeks since
his last blog post.
It's a long time since
I met him.
How long is it since
they moved away?
Related topics:
Present perfect with FOR and SINCE
Past simple to express a point in the past
Present perfect with quantities