present perfect

The prime factor which is felt to influence the use of the present perfect over the simple past is a writer's feeling that a past action is relevant to a particular current situation. This situation is to be found in the context of present perfect statements and would most naturally be expressed in the present tense. Two conditions for the use of the present perfect are then seen to be: 1) the existence of a situation to which past actions can be related, and 2) the expression of this situation in the present tense