Present Perfect, Present Perfect Progressive, and Simple Past

Simple Past and Present Perfect - Monash University

Simple Past and Present Perfect: ELC Study Zone UVic - Introduction and five exercises

Simple Past and Present Perfect - ESL at About.Com

Present Perfect - Grammar Quizzes

Simple Past and Present Perfect - ELC Study Zone UVic

Perfect or Progressive - ESL at About.Com

Past Time Tutorial - Net Grammar

Present Perfect Progressive - Teacher Video Explanation