Bill likes going to the zoo on Sunday. He likes animals very much. Last Sunday, it was sunny. Bill went there with his brother. They got there at 9: 00 a. m. There were lots of people in the zoo. Bill and his brother walked and watched the animals.
There was a panda show at 11:00 in the morning. Many people came to watch the show. Bill and his brother watched the show, too. It was very interesting and they were happy. But after the show, Bill found there were lots of water bottles on the ground. He also saw some paper bags on it. That made Bill sad. He and his brother began to pick up the bottles and bags. They worked hard. About twenty minutes later, the ground was clean. Then Bill put up a sign (指示), saying, "No littering (乱扔)". They wanted people to keep the zoo clean. After that, they had lunch at the zoo and went home.
