英语翻译

问题描述:

英语翻译
Famous explorers of the North American frontier,Lewis and Clark had experienced great difficulty finding game west of the Rockies and not until the second of December did they kill their first elk.
until the second of December did they kill their first elk.怎么理解,

北美边远地区著名的探险家们——Lewis和Clark在落基山脉西部找寻猎物时经历了巨大的困难,直到十二月的第二天他们才杀死他们的第一头美洲赤鹿.