Print the page in color so that you have enough for each student in your class (if you have 24 students, print the page 12 times). Cut each page in half. Put students in pairs giving each person in the pair half of the sheet. One student listens as the other reads the sentences with the correct form of the verb SER. When students get to the bottom of the sheet, they switch papers and do the drill again. In my classroom, students must repeat the drill until they are instructed to stop.
Check out some of my other pair drills:
Affirmative Tú Commands Pair Drill
Regular Preterite -er and -ir Verbs
Reflexive Verb Pair Drill
Preterite Stem Changing Verbs
This pair drill is included in my bundle of Spanish I Pair Drills.