If you want to know the time, you look at the clock.  In grammar, if you want to know when something happened, you look at the verb.
 
In Mr L's Conjugating Verbs Workbook you will learn about verb conjugation and the different verb tenses you need to be aware of when writing and speaking.
 
Included in this lesson is an explanation and over 10 exercises.
 
This grammar resource is suitable for age 11 and upwards.