失った時間を

lost time

→ 失う
phrase Rare #40,345
lost time 失った時間 means “lost time,” and を marks it as the object of the following verb. It commonly appears in phrases such as 失った時間を取り戻す, “make up for lost time.”
JA: 失った時間を取り戻すために、一生懸命勉強した。
EN: I studied hard to make up for lost time.

失った時間を金で埋め合わせることはできない

You can't make up for lost time with money.

彼は失った時間を取り戻そう急いだ

He hurried to make up for lost time.