Present Perfect Tense

A: Have you studied for the best?
B: Yes, I have. Even I have done all this weeks homework.
A: Good job!

The bold-typed sentences in the dialogue above use 'The Present Perfect Tense'. When you use the present perfect tense, there is a connection with the dialogue above, the boy doesn't need to study for the best and do all his home work for a week now because he has done all of them.

Patterns:

1. Positive Sentences (+)
S + have/has + (adverb*) + past participle + (O) + (adverb*)
2. Negative Sentences (-)
S + have/has + not + past participle + (O) + (adverb*)
3. Interrogative Sentences (?)
Have/Has + S + past participle + (O) + (adverb*) + ?

Info:

* a sentence using the present tense usually has only one adverb in time, either in the middle or ant the end of sentences.

You use the present perfect tense:

1. to express the idea that something happened (or never happened) before now the exact time it happened is not important.
examples:
1. I have seen the film already.
2. I have never drunk tea with milk.
If there's a specific mention of, time the simple past is used.
examples:
1. I saw the film yesterday.
2. I didn't drink the tea milk last night.
2. to express the repetition of an activity before now the exact time of each repetition is not important.
examples:
1. I have visited my uncle in USA twice.
2. Surya has made a cake two days ago.