The 50-something-year-old Yeh has been overseas for more than 30 years. The early period of his time abroad was spent in Africa where he was posted in Chad, Niger, and Dahomey as part of a farming team. Though he suffered from an attack of an anopheles mosquito (which carries malaria) while in Africa, he nonetheless feels that Peten has been his most difficult assignment, especially during the civil war.
年過五十的老葉在海外待了三十多年，早年在非洲農耕隊，去過查德、尼日、達荷美，雖然在非洲飽受瘧蚊攻擊，但是他覺得最辛苦的還是在北碇，尤其在內戰期間。