We learn from the passage that the boxes were used for

A few weeks before Valentine’s Day, the students were told to make boxes in which we would put our Valentine’s gifts. The day finally arrived. Each student put the box they had made on Mrs. Toalson’s desk. (5)One box had the words " I love you, basketball" written on it. Another box looked like a mailbox, while a box was in the shape of a dolphin. Mine was a pink piggy box with "Happy Valentine’s Day" written on it. Mrs. Toalson handed out pieces of paper. She then told us to vote for the "Best Boxes". The winners would be awarded certificates. After we voted, Mrs. Toalson asked us to collect our boxes and take out the gifts we had for our friends. She also took out a bag of gifts for us. All the students exchanged their gifts. I gave out shells from my hometown in China. Everyone loved them as they were so different. I was thrilled with all the gifts I had received: cards, bookmarks, pencils and chocolates. At last, Mrs. Toalson handed out the certificates for the winners of the best boxes. Everyone waited in anticipation. (6)"The cutest box is Mary’s pink piggy," Mrs. Toalson announced. Wow, I was one of the winners! As I received my certificate from Mrs. Toalson, she gave me a great big hug for my first Valentine’s Day.