The present perfect simple (for a past action with a present result)
We use the present perfect simple when we talk about the present result of a past action.
People have polluted the sea.
They have not taken care of animals.
Form: have/has + past participle (3rd form below).
polute polluted polluted
plant planted planted
destroy destroyed destroyed
be was/were been
cut cut cut
take took taken
Present perfect + already/yet (to talk bout time up to the present)
? yet (to ask if an action has been done)
A. Have you met her, yet?
– yet (to show that an action hasn’t been done up to now)
B. No, I haven’t met her, yet.
+ already (to show that an action happened sooner than expected)
C. Yes, I have already met her.