we use the present for :- 1.actions in a period of time up to the present: a-without time words: Mr Ragab has been to London and Paris. b-with (ever)and(never) : Have you ever been to London? No,I,ve never been to London. c-with (just,already and yet: Ow! I,ve just hit my foot! He,s already had his dinner . He hasn,t finished his homework yet. 2. actions which began in the past and continue into the present: I,ve been here for an hour . (for period of time ) I,ve been here since three o,clock.(since point in time) 3.past actions which have an effect on the present: Smeone has broken my window. (That,s why the glass is on the floor.) She,s finished her homework.(That,s why she,s put her books away.)