The difference between past simple and present perfect
Many students ask what is the difference between past simple and present perfect. They mention that in some languages they only have one tense for the past. We have two main tenses we can use to talk about the past.
The simple past
The simple past is the easy one. We use it to say when actions are completely finished. We use time expressions/cues such as last week, last month, 2 years ago, yesterday, etc… Those time expressions such as yesterday tell us the action was completed in the past.
We use the time expression, subject, verb and object to make the sentence:
Yesterday, I went to the cinema.
I understand that the time referring to yesterday is finished.
The present perfect simple
The present perfect simple is a little more complex. It can be used in several ways. We use time expressions such as NOW, this week, this month, this year, already, recently, yet, just and still. We refer to the time continuing or the action has just finished with a result.
This year I have studied a lot.
We refer to this year. The year is not finished. We are in the month of July 2019. The time continues.
Today I have cleaned my room. Today is not finished. It is only 8pm. We refer to Today. The day still continues.
We make the sentence with the time expression, subject, auxiliary and past participle:
Today I have cleaned my room. (regular verb – cleaned)
Today I have eaten a lot. (irregular verb – eaten)
The difference between these two examples
Yesterday I cleaned my room – PAST SIMPLE – Finished time
Today I have cleaned my room – PRESENT PERFECT SIMPLE – Unfinished time
Present perfect tense
We can use the present perfect when the action has just finished or there is a result:
It has rained. (It has just stopped) the result is the wet ground.
I have broken the vase. There are pieces of the vase on the floor. This is the result.
Unspecified time and specified time
We can use the present perfect for life experiences and unspecified time.
I have been to America. (you do not know when, but at sometime during my lifetime I went to America) To be exact, from the year I was born (1972) until NOW. My life continues.
We use the past simple for specified time. There is a specific time in the past.
Last year I went to America – the specific time is last year.
I have finished my homework (NOW is hidden in this sentence, but it means NOW).
I have finished the report. (just completed).
These are the most common examples. Now you can do the exercises using your grammar book or type in google esl past simple vs present perfect simple exercises and you will find plenty of exercises you can do as self-study. If you have a lesson, your teacher will be listening for the correct use of these two tenses. Listen to native speakers and try to understand why they have used those two tenses in their conversation.
Remember practise makes perfect
This is a useful idiom to mean that if you practise, you can only get better and then, eventually, you will reach perfection.