My life has been music, and a constant search for it has been the mainspring of my life.
我为音乐而生，对音乐的不懈探索已经成为我生活的动力。
《柯林斯英汉双解大词典》
You begin to understand what actions were the mainspring of the story.
你开始明白什么是这个故事的主要情节了。
《柯林斯英汉双解大词典》
In the early 1400s came the invention of the coiled spring or fusee which maintained constant force to the gear wheels of the timekeeper despite the changing tension of its mainspring.
