Daily Chinese Idiom Guessing Game
To spare no effort; to do something with all one's strength.
遗留；余力剩下的力量。把全部力量都使出来，一点不保留。
《战国策·赵策三》秦之攻我也，不遗余力矣，必以倦而归也。”《史记·平原君虞卿列传》秦不遗余力矣，必且欲破赵军。”
She worked on the project with total dedication, sparing no effort to meet the deadline.