Olefins
n. 烯烴; 鏈烯
??? 情景例句
Don't worry about it.
別放在心上。
My friend phoned me at 10 a.m. Yesterday.
我的朋友昨天上午10點打電話給我。
The search proved difficult, for the puma was often observed at one place in the morning and at another place twenty miles away in the evening.
事實上搜尋工作很困難，因為常常是早晨在甲地發現那只美洲獅，晚上卻在20英里外的乙地發現它的蹤跡。