Present Simple

We use both of these tenses for finished and unfinished actions.

The present perfect simple can be used (often with 'since' and 'for') to talk about unfinished actions that started in the past and are still true in the present. It's often used with stative verbs:

I've known John for three years.Present Perfect

The present perfect continuous can also be used (often with 'since' and 'for') to talk about unfinished actions that started in the past and are still true in the present. (Of course, we don't use the present perfect continuous with stative verbs):

• She's been living here for three years.

Sometimes there's really no difference in meaning between the two tenses. This is especially the case with verbs such as 'live', 'work' and 'study':

      They've lived in London since 2004.

Present simple:   I go to school by bus every day.

Present continuous : My mother is cooking in kitchen now.

Presen perfect : I haven't seen her for 4 months.