Study this example situation:
- John is looking for his key. He can't find it. He has lost his key.
"He has lost his key" means that he lost it a short time ago and he still doesn't have it.
Below are the forms of the present perfect tense:
Positive forms:
- I / we / they / you have (= I've, etc.) lost ... .
- He / she has (he's, etc.) lost ... .
Negative forms:
- I (etc.) haven't lost ... .
- He (etc.) hasn't lost ... .
Interrogative forms:
- Have you (etc.) lost ... ?
- Has he (etc.) lost ... ?
We form the present perfect tense with have/has + the past participle. The past participle form often ends in -ed (worked, typed, etc.), but many important verbs are irregular (lost, done, written, etc.).
When we use the present perfect tense, there is a connection with the present:
- I have lost my key. (= I don't have it now)
- Tom has gone to America. (= He is in America or on his way there now)
We often use the present perfect tense to give information or to announce a recent happening:
- I have lost my key. Can you help me look for it?
- Did you hear about Jane? He's gone to America.
You can use the present prefect with just (= a shot time ago):
- A: "Would like something to eat?". B: "No, thanks, I've just have had lunch".
- Hello, have you just arrived?
Use the present perfect tense with already to say something has happened sooner than expected:
- A: "Don't forget to lock the door". B: "I have already locked it".
- A: "When is John going to start his new job"? B: "He has already started".
Note that you can also use the simple past tense ( I did ... / I lost ... etc.) in the above situation:
- I lost my key (I have lost my key). Can you help me look for it?
- A: "Would like something to eat?". B: "No, thanks, I just had lunch (I've just had lunch)".
- A: "Don't forget to lock the door". B: "I already locked it (I have already locked it)".
Study the difference between gone to and been to:
- Julia is on vacation. She has gone to Indonesia. (She is there now or she is on her way there)
- Arthur is back from his vacation. He has been to Indonesia. (= He was there, but now he has come back)