Here's the completed text with the verbs in the past simple form:
Last Saturday my dad 1) took (take) my friend, Harry, and me to the circus. My Dad 2) bought (buy) us some popcorn and orange juice. We 3) saw (see) lots of things at the circus. There 4) were (be) some lions. They 5) did (do) some tricks; they 6) jumped (jump) through hoops. A girl 7) rode (ride) an elephant around the ring. We 8) had (have) a lovely time at the circus.