How to form and when to use Past Simple, Past Continuous and Present Perfect.
Students usually find it difficult to choose from Past Simple and Present Perfect so here you have an easy way to help them (page 4).
How to form and when to use mixed tenses. Explained in Spanish and with examples. I have used them (with great results) with students from 4ºESO and Bachillerato. They also work pretty well with adult students.