go back on a promise的用法和樣例：
例句
- He has never reneged on a promise.
他從來不食言。 - Forgive me for breaking my promise.
原諒我食言。 - Could a defaulter remain in the euro?
歐洲是否還有其他違約者？ - They are scrambling for cash to avoid defaulting on bank loans.
他們紛紛爭取現金以避免在銀行貸款上違約。 - I felt guilty after breaking my promise.
我違背諾言後感到內疚。 - We shouldn't rat on our promise.
我們不應該違背諾言。
