When to use already, Yet, Just, Ever, Never, For and Since??

I have been a doctor for fifteen years.

How to use already,Yet,Just?

express when the action

of a verb has been completed.

Already

present perfect (have+participle)

I have already finished my homework – Ya he acabado mis deberes

when there are doubts about whether

or not an action has occurred.

Yet

yet will go to the end of the sentence

We haven't finished an action yet.

negative sentences

I haven’t finished my homework yet – No he acabado mis deberes todavía.

Just

action has been completed very recently

after the auxiliary verb

and before the verb

I have just eaten. – Recién he comido.

NEVER AND EVER

are used to talk about things a person has done

without saying WHEN they happened

EVER:

indicates who we ask if

Something has happened to him

or he has done something.

Have you ever read the Harry Potter books?

¿Has leído algún libro de Harry Potter?

NEVER

reports that

we have not performed a certain action

We’ve never experienced any problems in our relationship.

Nunca hemos tenido problemas en nuestra relación.

FOR y SINCE

FOR

TO mention a specific period (or duration) of time

I have been a doctor for fifteen years.

SINCE

FROM to mention the starting point of a period of time (continues until now).

She has been pregnant since her first child was born.