First let’s understand the syntax –
Use has/have and 3rd form of verb to form present perfect sentence.
For example –
We have seen this movie. (see(1) saw(2) seen(3))
She has cleaned her room. (clean(1) cleaned(2) cleaned(3))
For some verbs (regular), the 2nd and 3rd forms are same. But in some verbs (irregular), both are different. For such verbs, we need to be careful to always use the 3rd form to get present perfect sentence.
Now, the usage –
1. When something just happened. Examples –
a. My friend has left for the match.
b. They have gone out.
c. We have seen the cat.
In the above sentences, we can also use past tense,
My friend just left for the match OR They just went out. OR We saw the cat just now.
2. Actions in the past, which have an effect on present
a. She has cleared her examinations (that were held sometime in the past)
b. I have taken leave for 5 days (for which I applied sometime in the past)
c. We have completed the exercises (which we started sometime in the past)
3. Actions that began in past, but are continuing in present
a. He has gone to UK for a week. (He is still in UK)
b. All the guests have arrived for the party.
4. When actions happened in recent past, but the definitive time is not known
a. I have waited for quite a long time now.
b. I have watched these series before on TV.
Most of the times while speaking, we skip the have/has and make the sentence as past simple sentence. This may be correct on some occasions as there is thin line of difference between past simple and present perfect for situations that have happened in immediate past. But, consider the following –
1. It’s now 1pm.
I saw her yesterday night (past)
I have seen her today morning (immediate past)
2. My maid did not come yesterday.
My maid has not come (today).
In this example, saying “my maid did not come today” is incorrect. “has not” is grammatically correct.
3. I lost my passport 3 years back (and probably got a new one by now)
I have lost my passport (and haven’t found it till now)
Again, saying “I lost my passport today morning” will be correct only if you have found it at the time of speaking. Otherwise, the correct one will be “have lost”
Few more examples to compare past simple and present perfect
Past action – I broke the biscuit jar.
Effect – Who has broken the biscuit jar? Where will I put the biscuits now?
I did my homework in the class itself, so I can go out and play whenever I want to.
I have done my homework so I can go out and play now.
We saw the movie yesterday night (definitive time)
We have seen the movie (but don’t know when)
A quick quiz – now that you have got the hang of it, complete the below sentences with the correct tense –
a. We _____ off all the lights. We are going to sleep. (switched off, have switched off)
b. They _____ my pen. They will return it tomorrow. (took, have taken)
c. They ____ my hat and never returned it. (took, have taken)
Don’t worry if you can’t them all right, you are sure to get perfect with perfect tense soon by more practise!