mainspring
US /ˈmeɪn.sprɪŋ/
UK /ˈmeɪn.sprɪŋ/
名詞
ぜんまい
the most important reason for something; the thing that makes something else happen:
例:
•
Work was the mainspring of his life.
ぜんまい
the most important reason for something; the thing that makes something else happen: