I have done and I did
- We use the present perfect for an action in the past with a result now.
o I’ve lost my book. (= I can’t find my book now)
o Jenifer is gone to bed. (She’s in bed now.)
Usually you can also use the simple past in these situations. So you can say:
o Where’s my book? I’ve lost it. … Or… I lost it.
o We’ve bought a new car. …or… We bought a new car.
- We use only the simple past (not the present perfect) with a finished time (yesterday, last week, etc.)
o I lost my book yesterday. (not I’ve lost)
o We bought a new car last month. (not we’ve bought)
Just, already and yet
- Just ( = a short time ago)
We use just with the present perfect or the simple past.
o Diane and Paul have just arrived. Or Diane and Paul just arrived.
o I’ve just have dinner. Or I just had dinner.
- Already ( = before you expected / before I expected)
We use already with the present perfect or the simple past.
o They’ve already arrived. Or They already arrived.
o We’ve already met. Or We already met.
- Yet ( = until now)
We use yet with the present perfect or simple past. We use yet in negative sentences
(I haven’t … yet) and questions (Have you… yet? Yet is usually at the end.
o Negative sentences
They haven’t arrived yet. Or They didn’t arrive yet.
I haven’t bought a new computer yet. Or I didn’t buy a new computer yet.
o Yet in questions
Have you bought a new computer yet? Or Did you buy a new computer yet?
Have you found another house yet? Or Did you find another house yet?
I’ve lost my key. I lost my key last week.
Sometimes you can use the present perfect (I have lost/ he has gone, etc.) or the simple past (I lost/ I went, etc.).
o Is John here? No, he’s gone to work. Or He went to work.
But with a finished time (yesterday / last week, etc.), we use only the simple past (not the present perfect).
o We arrived yesterday / last week / at 3 o’clock / in 1984 / six months ago.
Do not use the present perfect with a finished time.
o I saw her yesterday.
o Where were you last Saturday?
o What did you do last week.
Use the simple past to ask When….? Or What time …?
o When did you arrive?