Usages
Sheila has joined the Sierra Club.Sheila joined the Sierra Club.
The use of the present perfect has more to do with our present perspective on the event rather than on the actual time at which it took place.
The simple past tense occurs with specific past-time adverbials. The core meaning of the past tense is remoteness. The use of specific past-time adverbials (e.g., yesterday, last year, 1990) makes the past tense obligatory. The use of certain more general temporal adverbials is commonly associated with the perfect (e.g., already, since, yet).
Organise the phrases in the next slide into three columns headed used with simple past, used with present perfect and used with either.
Up to nowIn the last
century
During Kennedy’s
lifetime
Over the last hundred
years or so
For three months
Three months ago
Since three months ago
RecentlyThis is the first time I
LatelyThroughout
the 17th century
Since the Vietnam War
TodayWithin the last three months
After the Second
World War
In the last centuryduring Kennedy’s lifetimeThree months agoThroughout the 17th century
Up to nowOver the last hundred years or soSince three months agoThis is the first time ILatelySince the Vietnam WarWithin the last three months
For three monthsRecentlyTodayAfter the Second World War
Even if a past-time adverbial isn’t explicit, the remoteness may be defined elsewhere in the context or simply implied:
John Lennon was a creative genius.
The past tense is used for a completed historical period versus an incomplete one:
My father lived here all his life. My father has lived here all his life.
The function of the present perfect is to change the nature of the relationship between the subject and predicate – it emphasizes the predicated event’s result.
I’ve been to Japan twice already, but I still don’t speak much Japanese.
Past simple is used by speakers to talk about past events which are, or which they regard as, finalised, or over and done with.
Present perfect is used by speakers to talk about events which are still current, or which they want to highlight as being incomplete or still relevant.