In this lesson, we will look at the difference between Past Simple and Present Perfect Simple.
These are both very common, but different tenses that can be easily confused. They both talk about actions that happened in the past, but the main difference is that past simple actions are 100% finished and have no effect on the present. Present perfect actions started in the past and may or may not be finished, but it does have an effect on the present. This is why it is called 'present' perfect and not 'past' perfect.
We will take a detailed look at the forms of both Past Simple and Present Perfect Simple, and explore the functions (why we use them) of each.
FORM:
PAST SIMPLE:
PRESENT PERFECT SIMPLE:
FUNCTION:
1. SPECIFIC vs NON-SPECIFIC TIME
PAST SIMPLE = SPECIFIC TIME
I lived overseas in 2016.
Past simple is used to refer to a specific time in the past. Often, a specific time phrase is used (e.g. in 2016, last month, 2 hours ago, when I was a child etc.). In this example, it is very clear that you lived overseas in 2016.
PRESENT PERFECT SIMPLE = NON-SPECIFIC TIME
I have lived overseas.
Present perfect simple is used to refer to non-specific or unknown time. We cannot use a specific time phrase (like those above) but rather more generic time phrases (e.g. for 2 years, since 2016, in my life etc.). In this example, it is not clear when you lived overseas. More information on time phrases will be given in point #5.
2. FINISHED vs UNFINISHED ACTIONS
PAST SIMPLE = FINISHED ACTION
I lived overseas for 2 years.
Past simple is used to refer to a finished action in the past. As with the previous point, this action has no effect on the present, and therefore means that you do not live overseas in the present.
PRESENT PERFECT = UNFINISHED ACTION
I have lived overseas for five years.
Present perfect (simple and continuous) can be used to describe unfinished actions that started in the past. In this example, you started living overseas 5 years ago, and may still be living overseas today.
3. LIFE EXPERIENCE FOR THE DEAD vs THE LIVING
PAST SIMPLE = LIFE EXPERIENCE FOR DEAD PEOPLE
My great-grandmother lived overseas twice.
Past simple is used to describe life experiences of dead people. To be precise, this can be used to describe how many times someone has done something in their life (before they died).
PRESENT PERFECT SIMPLE = LIFE EXPERIENCE FOR LIVING PEOPLE
I have lived overseas three times.
Present perfect simple is used to describe life experiences of living people. It can also be used to describe how many times someone has done something in their life.
4. PAST ACTIONS WITHOUT A PRESENT EFFECT vs WITH A PRESENT EFFECT
PAST SIMPLE = PAST ACTIONS WITHOUT A PRESENT EFFECT
I lost my passport.
Past simple is used to talk about actions in the past that have no effect on the present. In this example, we would assume the passport was lost a long time ago, and therefore has no effect on the present. It's also possible it was lost more recently, but still does not have any effect on the present. It's possible that you found the passport again, or you ordered a new one, therefore making the problem irrelevant today.
PRESENT PERFECT SIMPLE = PAST ACTIONS WITH A PRESENT EFFECT
I have lost my passport.
Present perfect simple is used to talk about an action in the past that has an effect on the present. It is clear from context whether the action is finished or not. In this example, we can see that the action is finished (i.e. the passport is lost), but the effect of this is very relevant in the present. For example, we can interpret this as a cry for help (i.e. Please help me look for it), or the result or consequence of this is significant (i.e. I cannot travel overseas anymore).
5. FINISHED vs UNFINISHED TIME EXPRESSIONS
PAST SIMPLE = FINISHED TIME EXPRESSIONS
I visited the museum | yesterday. | on Monday. | last month. | last year. | in 2018. | two years ago.
Past simple uses finished time expressions like those above.
PRESENT PERFECT = UNFINISHED TIME EXPRESIONS/ADVERBS
I have visited the museum | today. | this month. | this year.
Present perfect uses unfinished time expressions like those above.
I have | already | visited the museum. I have | just | visited the museum.
We can also use 'already' to talk about a finished action that happened earlier than expected. We can use 'just' to talk about a finished action that happened very recently.
I haven't visited the museum | yet. Have you visited the museum | yet?
We can use 'yet' with negative statements and questions to indicate an action that we expect to happen soon.
I have lived overseas for 4 years. I have lived overseas since | 4 years ago. | 2016.
We can use 'for + time' to indicate how long or the duration of an activity. We can use 'since + specific time' to indicate the same thing, but using a specific time to show when the activity started.