Present Perfect. Utilizzi il verbo nel present perfect che corrisponde. Utilizzi i verbi to change, to show, to ask, to stand, to go, to know, to want, to be, to try, to purchase

http://www.inglese-online.de/grammatica/capitolo33/33_1_3_1_present_perfect.htm

 Present Perfect. Utilizzi il verbo nel present perfect che corrisponde. Utilizzi i verbi to change, to show, to ask, to stand, to go, to know, to want, to be, to try, to purchase