arrears
n[pl]
1 money that is owed and should have been paid earlier (過時未付的)欠款
arrears of salary 欠薪 * rent arrears 欠租.
2 work that has not yet been done 未做完的工作
arrears of correspondence, ie letters waiting to be answered 待覆的信件.
3 (idm 習語) be in/fall into arrears (with sth)
(a) be late in paying money that is owed 拖欠
I have fallen into arrears with my rent. 我已經拖欠租金了.
Payment is made in arrears, ie at the end of the period in which eg the work was done. 後行付款(在最後的一段時間付款, 例如工作完成後).
(b) be late in doing work that is necessary 拖延(應做的事)
I'm in arrears with the housework. 我的家務事還拖著呢.