Present Perfect Tense or PPT :DD

I have sung *???*

present perfect tense is a rather important tense in english, but it gives speakers of some languages a difficult time. that's because it uses concepts ideas that don't exist in these languages. in fact, the structure of present tense is very simple. the problem come in usage between British and American English.

the structure of the present perfect tense is :
subject + auxiliary verb *have* + main verb *past principle*


+ i have seen ET
you have eaten mine

- she has not been to Rome
we have not played football

? have you finished ?
have they done it ?


i have become i've
you have become you've
he has become he's
she has become she's
it has become it's
John has become John's


here are some example from PPT :
i've finished my work.