Present Perfect Discussion

Yet ​is used in negative sentences and questions.

We use it for things we haven't done yet, but we expect to do soon.

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My Wednesday, 10 am class, have already travelled to London, and they enjoyed it.

Already ​is used in positive sentences and questions.

We use it for things we have already done before now.

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I have already travelled abroad. ​

Students has just finished debating the question.

Just ​

We use it for things we have done a very short time ago.

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I have already travelled abroad. ​

Present perfect simple is for an action that is completed:
I've driven an automatic car before.

Present perfect continuous is an activity that is still continuing or has just ended:
I've been driving since nine o'clock

Present perfect continuous is sometimes used to explain the cause

Why is he looking dirty?
He has been repairing the car.

Questions with how much? how many? are often asked with present perfect simple

Questions with long? are often asked with present perfect continuous

Time expressions with present perfect simple: always, recently, before, ever, already.

Time expressions with present perfect continuous: for, since