Segítene valaki elmagyarázni nekem az alábbi igeidők közötti különbséget?

(Yesterday), I drank my coffe: tegnap megittam a kávémat.

I have already drunk my coffe: (Már) megittam a kávémat.

I have been drinking my coffe (since morning): Reggel óta iszom a kávémat. (Még most is iszom, és még inni is fogom, rossz példa, tudom:)

Néhány példa:

She woke up, washed herself, cleaned her teeth, took a shower, combed her hair, and prepared a cup of coffee and drank it.

She's drunk the poison and, oh my gosh, nothing has happened.

You've been sipping your coffee for an hour now. Why do you nee such a long time to accomplish anything?

rRata:

A "nothing has happened" helyett "nothing had happened" (Past Perfect).