1.In three years, I will have paid off the difference with this, and I don't have to be the person who's always on call to milk.
pay off 付清;取得成功;賄賂;報復
He paid off the debt of his friend with the money raised by his writings.
他用稿費的收入償清了朋友的債務 。
It has been rather costly to install the machinery, but it should pay off in the long run.
安裝這套機械代價很高,但從長遠來看它會賺錢的 。