Ask one question: is the time finished? I lost my keys yesterday uses the past simple, because yesterday is over. I've lost my keys uses the present perfect, because the keys are still missing right now. Everything else follows from that.
This is the single most common mistake English learners make past A2, and it is not really about grammar. Both sentences describe the same event. They differ in what you are pointing at: the event itself, or the situation it left behind.
The question that decides it
Before you choose a form, ask where your attention is. If you are telling someone when something happened, you want the past simple. If you are telling them how things are now because of it, you want the present perfect.
Try it on a pair. I broke my arm answers "what happened to you?". I've broken my arm answers "why are you wearing that cast?". The event is identical. The first sentence puts it in the past and leaves it there; the second brings it forward to explain the present.
Here are four more pairs. Read each one aloud and ask yourself who would say it and why:
- She wrote three books. She has stopped writing, or she has died. She has written three books. She is still a writer, and there may be a fourth.
- Did you see the email? You are asking about a closed moment, perhaps this morning. Have you seen the email? You are asking whether the information has reached them by now.
- I lived in Prague for two years. You do not live there any more. I have lived in Prague for two years. You still live there.
- We finished the report. A fact about yesterday. We have finished the report. It is ready, so you can send it.
Native speakers do not run this test consciously. They hear a finished time word and the past simple arrives on its own. You can get to the same place, but you get there by making the test deliberate for a few weeks first.
One sentence, four jobs
The past simple sentence carries a time marker. That marker is what locks the sentence into finished time, and it is the part the present perfect cannot have.
Every part is doing one job. Change the time word and the whole sentence changes tense.
I lost my keys yesterday.
A finished event, at a stated time. The story is closed.
- I The subject. In the past simple it never changes the verb: I lost, she lost, they lost.
- lost The past form of lose. Irregular, so no -ed.
- my keys What the verb acts on. Unaffected by tense.
- yesterday The part that decides everything. A closed time word forces the past simple; remove it and I've lost my keys becomes the natural sentence.
subjectverbobjecttime
The present perfect has a different shape. It needs two words where the past simple needs one: have or has, then the past participle. I have lost, she has lost, they have taken. In speech both shrink, so you will hear I've lost and she's lost far more often than the full form.
That contraction is why learners miss the present perfect when listening. She's lost her passport sounds like one short word before lost. Train your ear on it and half the confusion disappears.
Where the line falls
Think of where the sentence sits in time. The past simple drops the event into closed time and leaves it there. The present perfect stretches from the event up to the moment you are speaking, which is exactly why it refuses to sit next to yesterday.
The same logic explains a pair that confuses almost everyone. Have you been to Japan? asks about your whole life up to now, so the period is still open. Did you go to Japan? asks about a trip both of you already have in mind, perhaps last summer, so the period is closed.
It also explains why the present perfect is common in news openings and rare in the rest of the story. A report begins A train has derailed near Leeds, because the situation is live. The next sentence switches: It left the track at 6.40 this morning. Once a time is named, the past simple takes over.
The time words choose for you
Most of the time you do not have to reason at all. A single word in the sentence has already decided. Learn these two columns and you will be right far more often than you are wrong.
| Past simple | Present perfect | Why |
|---|---|---|
| yesterday, last night, in 2019 | A closed period. The present perfect cannot name a finished time. | |
| two hours ago, when I was a student | Ago measures back from now to a finished point. | |
| already, yet, just | They describe the situation as it stands now. | |
| since 2019, for three years | The period started in the past and has not closed. | |
| ever, never, so far | They cover your whole life up to this moment. | |
| this morning (it is now evening) | this morning (it is still morning) | The same words, depending on whether the period is over. |
Watch the last row, because it catches people out. This morning, today, this week and this year belong to either column. At 10 a.m. you say I've had two coffees this morning, because the morning is still running. At 9 p.m. the same sentence needs I had two coffees this morning.
One more trap: for. It appears in both columns and the form decides the meaning. I worked there for five years means you left. I have worked there for five years means you are still there. Nothing in the time phrase tells you which; only the verb does.
✦ Test yourself
Five questions. Every answer explained.
The same choice, in sentences you would actually say. No sign-up, no score saved.
I ___ a film last night.
"I ___ my phone. Can I borrow yours?"
She ___ in Berlin since 2019.
He came in, ___ his coat and sat down.
It is 9 p.m. Which is right?
Slova turns the ones you missed into a ten-minute lesson, in sentences about your own week.
Practise this in Slova →Three mistakes worth fixing first
Each of these is small and each one marks you out immediately. They are also quick to fix, because every one comes from the same confusion about finished time.
- "I have seen it yesterday." A finished time word cannot follow the present perfect. Say I saw it yesterday. If you want the present perfect, drop the time word: I've seen it.
- "I am here since Monday." A period that started in the past and continues takes the present perfect: I have been here since Monday. This is especially common for speakers of French, German, Spanish and Turkish, whose languages use the present here.
- "Did you finish yet?" Standard British English wants Have you finished yet? American English accepts the past simple, so you will hear both, but only one is safe in an exam.
A fourth is worth watching even though it is less visible. Many learners use the present perfect for a sequence of events, because it feels more recent: I have arrived, I have opened the door, I have sat down. English does not tell stories that way. Once you start narrating, every step takes the past simple, however recent it was.
Still slipping on this one? Tell Slova and it builds you a mini path on this contrast alone: a few short lessons, in sentences about your own week, with a tutor that corrects you as you speak.
Build a mini path →Questions and negatives follow the same rule
The choice does not change when you ask or deny something. It only looks harder because the auxiliary moves to the front and the main verb goes back to its base form.
In the past simple, did carries the tense and the verb stops carrying it: Did you send it?, not Did you sent it. The negative works the same way: I didn’t send it. In the present perfect, have and has do that job: Have you sent it? and I haven’t sent it.
| Past simple | Present perfect | What you are asking |
|---|---|---|
| Did you call her? | Have you called her? | A known moment, against: at any point up to now. |
| I didn’t read it. | I haven’t read it. | It did not happen then, against: it has still not happened. |
| Where did you go? | Where have you been? | A finished trip, against: your whereabouts until this moment. |
Never and ever belong to the present perfect because they cover your whole life so far: Have you ever eaten oysters?, I have never been to Rome. Put a finished time next to them and the sentence breaks: I have never been to Rome last year is not English.
Conclusion
The past simple and the present perfect are not two ways of saying the same thing. One points at an event in closed time; the other points at the situation that event left behind. A finished time word settles the question almost every time, and when there is no time word, you are choosing what you want your listener to care about. Practise the choice out loud on sentences about your own week, and get corrected when you slip. The rule becomes a reflex faster than you expect.
Frequently asked questions
Is "I have seen it yesterday" ever correct?
No, not in standard English. A finished time word requires the past simple: I saw it yesterday. Drop the time word and the present perfect becomes natural again.
Do Americans really use the past simple more?
Yes. "Did you eat yet?" is normal in American English where British English prefers "Have you eaten yet?". Both are understood everywhere, but exams expect the British pattern.
What about "this morning"?
It depends on the clock. While it is still morning the period is open, so the present perfect works. Once it is afternoon the period has closed and you need the past simple.
How long does this take to get right?
Most learners stop making the obvious mistakes within a few weeks of deliberate practice. Getting it right at speed takes longer and comes from speaking rather than from exercises.
Sources
- Council of Europe. Common European Framework of Reference for Languages: level descriptions. where this contrast sits in the A2-B1 range
- Swain, M. (1985). Communicative competence: Some roles of comprehensible input and comprehensible output in its development. In S. Gass & C. Madden (Eds.), Input in second language acquisition (pp. 235-253). Newbury House. producing the form, not just recognising it, is what fixes it
- Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving students' learning with effective learning techniques. Psychological Science in the Public Interest, 14(1), 4-58. practice testing and spaced review rated high utility