1
be regretful about/for sth
She is still regretful about her decision.
她仍对自己的决定感到遗憾。
感到惋惜的；遗憾的；抱歉的
先理解核心含义，再看它在真实句子里的用法。
感到惋惜的；遗憾的；抱歉的
feeling or showing regret or sorrow over something done or not done
She is still regretful about her decision.
她仍对自己的决定感到遗憾。
充满遗憾的感觉,沉浸在遗憾中。
Full of feelings of regret, indulging in regrets.
对失去或做过的事情感到悲伤。
Sorrowful about what has been lost or done.
She felt regretful about missing her friend's wedding.
她为错过朋友的婚礼感到惋惜。
He gave a regretful smile as he handed back the borrowed book.
他归还借来的书时露出了抱歉的微笑。
They were regretful for the harsh words they had said.
他们为自己说过的刻薄话感到后悔。
She is still regretful about her decision.
她仍对自己的决定感到遗憾。
后接完整从句。
He is regretful that he missed the opportunity.
他很遗憾错过了那次机会。
多用于正式道歉或通知。
We are regretful to inform you of the cancellation.
我们很抱歉通知您取消事宜。
Not this
I am regretful to say that I cannot attend.
Use this
I regret to say that I cannot attend.
regretful是形容词，意为“感到遗憾的”，通常描述人的感受，而“regret to say”是固定搭配，使用动词regret更为自然。因此，应将“regretful”改为动词形式“regret”。
Not this
This is a regretful situation.
Use this
This is a regrettable situation.
regretful描述某人感到遗憾，而regrettable描述某事令人遗憾。形容“情况”时应用regrettable。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
对……感到遗憾/懊悔
She was regretful about the harsh words she had said.
她对自己说过的刻薄话感到懊悔。
为……感到抱歉/遗憾
He felt regretful for missing his daughter's recital.
他为错过女儿的独奏会感到遗憾。
感到遗憾
I feel regretful that we never got to say goodbye.
我为我们没能告别感到遗憾。
遗憾的叹息
With a regretful sigh, she closed the old photo album.
她遗憾地叹了口气，合上了旧相册。
懊悔的神情
He gave a regretful look at the empty seat beside him.
他懊悔地看了一眼身旁的空座位。
后悔的语气
Her regretful tone made it clear she wished she had stayed.
她后悔的语气清楚地表明她希望自己留下来。
Use regretful naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
regret（后悔）+ -ful（充满）→ 满心后悔的，像一直念叨“要是当初……”的感觉。
语域：formal 常见场景：正式书信、公开讲话 regretful 比较正式，多用于书面或正式场合，表示对已发生事情的遗憾或歉意；日常口语中更常用 sorry 或 regret，选择时需注意语气。
常与 about/for 连用，表示对某事感到遗憾或抱歉。
Dictionary facts from ECDICT, WIKTIONARY.