40 back out; back out from; back out of; break one’s word; break one’s promise; go back from; go back of; go back on; go back upon

● 本组词组均有“食言”之意。

● back out中的out为副词，常跟of, from,成为back out from; back out of后接具体失信的内容了。如：I promised to help you and I’m not backing out now.（我答应过帮助你，那我现在就不能食言。）If you don’t follow my advice, I would back out of my words.（如果你不按我的主意去做，我就收回我的诺言。）You can’t back out from [of] a contract once you’ve signed it.（你一旦在合同上签了字，你就得履行合同。）I hope I can depend on you to continue your support and not back out at the last moment.（我希望你继续支持，不要在最后一刻变卦。）

● break one’s word和break one’s promise可互换。word与promise不变复数。如：No one wishes to deal with a person who is accustomed to breaking his word [promise].（谁不愿与惯于食言的人打交道。）Mary has broken her word [promise] so many times that I cannot trust her any more.（玛丽多次说话不算话，我再也不信任她了。）You can trust him; he is not the kind of person who will easily break his word [promise].（你可以信任他，他可不是那种轻易不守诺言的人。）In dealing with others she has never broken her word [promise].（和别人相处，她从未失信过。）

● go back on; go back upon; go back from; go back of均属动副介型词组，常用一般时态，一般少用被动语态。这些词组常含不忠之意，以上四个词组一般可互换。如：The person cannot be trusted because he consistently lies and goes back upon his promise.（此人不可信，因为他一贯撒谎，违背诺言。）He went back on [upon] his word not to tell my wife about the truth of my illness.（他违背了诺言，把我的病情告诉了我妻子。）He’s not the sort of man who would go back on [upon] his word.（他可不是那种言而无信的人。）Don’t go back of your word.（别说了不算数啊。）Never go back from your friend.（永远不要出卖你的朋友。）