心血 (xīn xuè): heart's blood; expenditure (for some project); meticulous care

In order to finish this novel, he devoted ten whole years of painstaking effort, revising it countless times.

The teacher poured all her heart and soul into her students; seeing them improve made her happier than anything.

My parents devoted most of their lives' hard work to this family; we children must learn to be grateful.

This garden was cultivated bit by bit with Grandfather's painstaking care after he retired; every flower is like his child.

After three years of the team's painstaking effort, the project finally succeeded, and everyone was so moved that they shed tears.