1.sigh的基本意思是“叹息,叹气”,指无意识地发出表示强烈渴望、失去信心、悲痛、思念、悔恨、沮丧、厌倦等情绪的深深叹息,是一种不情愿的情感表达。
2.sigh可用作不及物动词,也可用作及物动词。用作及物动词时,接名词或代词作宾语,也可接同源宾语。
3.sigh可引出直接引语。

sigh about〔for,over〕 (v.+prep.)
因…叹息,悲叹 breathe loudly, expressing a feeling, usually sad, on count of (sth or sb)
▲sigh about〔for,over〕 sb/sth
It's no good sighing about your failure, it is better to start again.为失败叹息毫无益处,最好是从头做起。
Sighing for sorrow can be harmful.悲哀叹息会伤害身体。
She sighed over her unhappy fate.她悲叹自己的不幸的命运。
I hope you are not still sighing over that boy.我希望你不再为那个小伙子伤心叹息。
The teacher told him not to sigh over the failure of yesterday's test.老师告诉他不要为昨天考试不及格叹息。

sigh away(v.+adv.)
连声悲叹 continuously breathe loudly expressing a feeling, usually sad
▲sigh away
By sighing away for hours, she hoped to attract her family's attention to her suffering.她一连几个小时老是叹气,希望引起家里人关心她的痛苦。
▲sigh sth⇔away
You can sigh away half your youth if you choose to allow failed relationship to sadden you.如果你陷于失败的伤感中,你就会使前半生在叹息中度过。

用作不及物动词
▲S+～(+A)
She put down the phone, sighed, and shook her head sadly.她放下电话,叹着气,悲伤地摇了摇头。
He thought of all the opportunities he had missed, and sighed.他想到已错过的一切机会,便叹了一口气。
The wind sighed in the treetops.风吹树梢发出轻微的啸声。
When he finished his homework, he sighed with relief.他完成了家庭作业后,轻松地舒了口气。
She sighed with relief when she heard the good news.听到这个好消息时,她宽慰地舒了口气。
用作及物动词
▲S+～+n./pron.
Mary sighed her relief.玛丽宽慰地舒了一口气。
He sighed a deep sigh.他深深地叹了一口气。
She sighed her reluctant agreement to the proposal.她叹息表示她勉强同意这个建议。
She sighed her sad experiences out.她叹息地说出了自己的不幸。
▲引出直接引语
“I've still got several hours' work to do,”he sighed.“我还有几个小时的工作要做。”他叹息着说。
“Where can I find enough courage to see me through this struggle?”Mary sighed.玛丽叹道:“我从哪里可以找到足够的勇气来支持我的斗争?”

sigh for, ache for, die for, hunger for, long for, starve for, thirst for
参见ache条。

The old man gave a deep sigh.那老人深深地叹了口气。
We all make a sigh of relief when we heard that he was safe.听说他平安无事,我们都松了一口气。