H。H CH3 ℃=C -C-&H 7,7-二甲基二环2.2.1川-2,5-庚二烯 (2Z,4Z☑-2,4-己二烯CH3 C=C CH3 H H H H C=C 7,7-二甲基二环[2.2.1]-2,5-庚二烯 (2Z,4Z)-2,4-己二烯