一、英譯中：請將以下英文譯成流利的中文（25 分）  The amazing contagiousness of laughter works across species. At the primate centerwhere I work, I often hear chimpanzees laugh when they tickle one another, and I cannotsuppress a chuckle in response. Tickling must be the original context of laughter, and thefact that tickling oneself is notoriously ineffective confirms its social significance.Tickling and laughter are essentially play patterns, with the latter having achieved aconsiderably expanded meaning in our species.