When we talk about experience or results, we use the present perfect form.

This form uses have followed by the participle.

For regular verbs, this participle is identical to the past tense form.

For irregular verbs, this participle is often different.

When we use the perfect form, the primary focus is on the subject of the sentence, not the verb.

It emphasizes condition experience results rather than actions or events.

In these two examples, we see the contrast.

She had already left the hotel.

She left the hotel a few minutes ago.

The Top sentence gives the condition or state of the subject. And the bottom sentence expresses an event.

The Top sentence describes the condition of the subject of the sentence she rather than an event.

The fact that she has left the hotel is now part of her experience or state of being.

The bottom sentence expresses the action or that she left, which is something she did.

In general, the past tense form expresses events or acts. And the perfect form expresses experience or conditions.

When we use the perfect form of the verb, we focus on the state of the subject and not an action or event.

Note that the past form expresses events at specific points or periods of time, such as last year or the past five years.

These events are distanced from the speaker's point of view.

The perfect form expresses the state of something from the speaker's point of view, not distance in time.

These two sentences are incorrect and confusing because they give two different points of view.

Which sentence is strange? He finished his work an hour ago. He has finished his work. He has finished his work last week.

Here are some sentences that use the perfect form.

Some are simple, such as the first one, and some are complex, like the last one.

The last one is complex because it combines many verb forms, including the passive.

He has practiced hard. So he should do well in the competition.

He may have been injured in the explosion.

The game has started already.

He may have taken his computer with him, but I'm not sure if he did or not.

One of the biggest areas of confusion for students is the difference between the  Past tense and the present perfect.

  In general, the past tense from expresses events or acts. And the perfect for me expresses experience or conditions.