Present Perfect vs Past Simple

If you are learning English, you have probably asked this question:

“Should I say I did or I have done?”

This is one of the most common problems for ESL learners. The good news is — you don’t need complicated rules. You just need to understand when we talk about time and when we don’t.

Let’s make it simple and practical.

Past Simple: Finished Time

We use Past Simple when an action is finished and we know when it happened, or it feels clearly in the past.

Structure: subject + past verb (regular: -ed, irregular: different form)

Example: I worked yesterday. / I went home.

This tense is often used with time markers like: yesterday, last week, last year, in 2020, two days ago.

For example:

• I watched that movie yesterday.
• She finished her homework last night.
• We visited Paris in 2019.
• I woke up at 7 a.m.

Even if we don’t say the exact time, the action still feels complete: I saw him at the party.

When you use Past Simple, you are thinking about a finished moment in the past.

Dr. James Mortimer entered. He was tall and thin. He had a long nose and sharp grey eyes behind gold glasses. His clothes were neat but worn. He looked kind but a little strange.

The Hound of the Baskervilles (adapted), Arthur Conan DoyleOpen book

Present Perfect: Time Not Finished or Not Important

We use Present Perfect when we don’t say when something happened, or when the result is important now.

The structure is: have / has + past participle

This tense is often used with time markers like: just, already, yet, ever, never, today, this week, this year (if the time is not finished).

For example:

• I have seen that movie.
• She has finished her homework.
• We have visited Paris.

We also use it for life experience: I have been to Italy. or Have you ever tried sushi? or I have never seen snow.

And for results that matter now: I have lost my keys. (I can’t open the door now) or She has broken her phone. (It doesn’t work now)

We can also use it with unfinished time: I have studied a lot today. or She has worked hard this week.

When you use Present Perfect, you are connecting the past to now.

I still do not believe in a supernatural hound. Yet I have heard a sound like a hound twice.

The Hound of the Baskervilles (adapted), Arthur Conan DoyleOpen book

Past Simple vs Present Perfect (Comparison)

The main difference is about time.

• I watched that movie yesterday. → we know when (Past Simple)

• I have watched that movie. → we don’t say when (Present Perfect)

• She lost her keys yesterday. → finished time, the situation was resolved.

• She has lost her keys. → result now (she still doesn’t have them)

We ate lunch at Merripit House that day, and Sir Henry met Miss Stapleton there. Since then we have seen them often. They are coming to dinner here tonight.

The Hound of the Baskervilles (adapted), Arthur Conan DoyleOpen book

One important rule: We cannot use Present Perfect with finished time like yesterday.

Another example:

• I studied a lot yesterday. → finished action
• I have studied a lot today. → today is not finished, I might study some more.

Quick Practice

Choose the correct form:

1. I (have seen / saw) that movie last week.
2. She (has finished / finished) her work already.
3. We (have visited / visited) Paris in 2018.
4. I (have lost / lost) my keys. I can’t find them.
5. He (has just arrived / arrived just) home.
6. They (have met / met) their teacher yesterday.
7. I (have read / read) two books this week, and today is only Friday!

Answers:

1. saw
2. has finished
3. visited
4. have lost
5. has just arrived
6. met
7. have read

Final Thoughts

Present Perfect and Past Simple are different, but not difficult. If you remember one thing, remember this:

• Past Simple = finished time, specific event
• Present Perfect = not finished, connection to now

So, should you say I did or I have done?

Use “I did” (Past Simple) when you are talking about a specific time in the past: I did my homework yesterday.

Use “I have done” (Present Perfect) when you are talking about your experience in general or something that is connected to now: I have done my homework. (It’s finished now) or I have done many interesting things in my life. (Experience)

If you can answer the question “When?”, use Past Simple. If the exact time is not important, use Present Perfect.

With practice, you will start to feel the difference and your English will sound more natural and confident.