柑橘类水果的清新香气主要来自它们所含的萜烯。

The fresh fragrance of citrus fruits mainly comes from the ___terpenes they contain.

蒎烯是一种带有松木香气的萜烯，常用于制造香水和肥皂。

Pinene, a pine-smelling ___terpene, is often used in making perfumes and soaps.

柠檬烯是一种能提升情绪的萜烯，常见于柑橘类水果中。

Limonene, a mood-boosting ___terpene, is commonly found in citrus fruits.