This is an activity for students to practice and/or review the Irregular Preterit. It covers Car/Gar/Zar, Irregular stems, and Dar/Ver. They use the key and color hte gum balls accordingly. This activity is different because the conjugation is done for them, they are just focusing on the ending to determine the subject. It is also easy to grade because you just check that the colors are correct!
I left it in the Word format so you can change the fonts, or any verbs your students may not know yet. You could also adapt it to the present tense!