An activity taking place at the present time may be expressed in English by the following tenses.
The Present Perfect
The Present Perfect is also used for an activity beginning in the past - which is indicated by an adverbial phrase of time - and continuing..
The Present Perfect Progressive
The present perfect progressive is used for an activity begun at some time in the past - indicated by an adverbial phrase of time - and continuing at the moment of speaking.
The Simple Present Tense
The simple present tense is used for a continual activity. For an activity which is repeated at some regular intervals. Examples of The Simple Present