单词	F region
释义	F region noun : the highest region of the ionosphere occurring from 80 miles (130 kilometers) to more than 300 miles (500 kilometers) Word History First Known Use 1923, in the meaning defined above
随便看	situation ethics situational situational neurosis situationally situationism situationist situations situations vacant situla situlae situps situs situses situtunga situtungas Sitwell sitz bath sitzkrieg sitzkriegs sitzmark sitzmarks Siuai siuais Sium siums

英语词典包含469781条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。