present perfect tense???

1)She' s been smoking too much recently.
2)What have you been doing since we last met?
3) Have you been playing tennis? ( your sentences here)

This tense is called " PRESENT PERFECT CONTINUOUS(PROGRESSIVE) TENSE".
Subject ( she) + has + been + verb+ing + adverb( since, recently, etc)
He/she/it + HAS + been + verb+ing
They/we/you/I + HAVE + been+ verb+ing
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When do we use this tense?
Let's take 2) for an example.
since we met<---------------- After we met<------
then you have been doing things right?
The question is what it means.
You have been doing<--------= Since we met, what you have been doing
( you started doing something right after we met)
( Now I want to know what you have been doing UP TO NOW)
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Let's move on to 3).
Have you been playing tennis?
It means you are still playing tennis while someone is asking you this question.
Let's say you started playing tennis at noon, you may answer
I have been playing tennis since noon. =
( You started playing tennis at noon. When someone asks you this question, you are still PLAYING TENNIS.)
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How have you been? <-------present perfect tense here
The asker expects you to say things like
I have been just fine.<------- example
This tense is usually used to show a recent complete action.
I have taken the med. <------------------Complete
I have told my mother about it. <-----------Complete
To talk about your experiences
I have曾經 been to Japan twice.
To talk about things you HAVE 已經done
I have told you so many times. You never listen to me!!
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I have watched the show 3 times. ( Say this if the show is not over)
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If the show is over, you should use simple past tense.

I watched the show 3 times.

將時間看成一條線,
past tense是過去的一點,
present perfect tense 就是由過去至現在的一段。

以上三句都是關於"最近一段時間"的活動, 所以用present perfect tense。

希望幫到你。