What is the topic sentence? my first time on horseback was embarrassing. i had never been on a horse in my life, but i was afraid to admit it. that’s probably where my trouble started. when i lifted my foot to put it into the stirrup, my friend sally laughed. “use the other foot, silly,” she said. blushing beet red, i laughed too. i used the other foot. then it took me about 10 minutes to swing up into the saddle. the horse kept moving and i scampered along on one foot while sally giggled. finally mounted, i looked down. i felt as if i were sitting on a mountain! fortunately, sally had chosen a gentle mare for me. i realize now she wasn’t fooled. she knew i didn’t know the first thing about riding. she really is a good friend. after a while, i learned to relax a little. i was actually riding a horse and it was fun. i even learned how to use the reins to guide the horse to the left and to the right.