An unsaturated bicyclic hydrocarbon, C₇H₈, structurally related to norbornane but with two CC bonds; bicyclo[2.2.1]-hept-2,5-diene.
1950s.
英汉双解词典包含464360条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。