[susan53]

I’m interested in when American speakers use the Present Perfect Simple and when the Simple Past. It seems to me that it’s only the final category below where the use differs from British English but I may be wrong, so I’m including examples of all uses. If you’re an American, let me know how you feel about the following :

Category One : Past and Present events

a) With non-ambiguous time phrases

I’ve lived here since 2001. I haven’t seen John for the last two days

Here, for a British speaker the simple past is not an option.

b) With ambiguous time phrases

I’ve had a headache all day. I’ve lived here for 6 years.

The time phrases are ambiguous because seen alone all day could mean all today or all last Tuesday; for six years could mean since 2000 or from 1992 to 1998. It's the verb form which disambiguates - the use of the present perfect indicates the first meaning, the use of the simple past the second. Therefore again they are not alternatives.

Category Two : Past Events with Present Results

The taxi has arrived. I’ve cut my finger.

Here, The taxi has arrived has no alternative – the speaker is inevitably saying “the taxi is here now”. But the second example might be expressed in the simple past, and would become more and more likely to be expressed in the simple past as time passed.

Category Three : Past Events in Past and Present Time Reference

I’ve seen three films this week.
Have you ever ridden a camel?
I haven’t prepared the lesson yet.
I’ve never read “War and Peace”
I’ve already done this exercise.

Here, there is the alternative of using the Simple Past, even for British speakers. It’s a matter of frequency – I don’t know if any research has actually been done but let’s hypothesise it’s about 80% use of the Present Perfect, 20% Simple Past. I’m interested in knowing whether you feel American speakers would never use the present Perfect for this use, or whether for Americans too it’s a matter of frequency – but with the Simple past being used more often than the Present Perfect.