他们的父母无可奈何地应允了这门亲事.用英语怎么说？

他们的父母无可奈何地应允了这门亲事.

Their parents unwillingly [ grudgingly ] consented to the marriage.

their

pron. 他（她，它）们的，在提及性别不详的人时，用以代替 him 或 her；

例句
Their permissiveness toward their children reflects the wild abandon of their own lives.
他们对孩子的放任折射出他们自身生活的放浪形骸。

parents

n. 双亲（ parent的名词复数 ）；

例句
Some parents believe a boy must learn to stand up and fight like a man.
有些父母认为男孩子必须学会像男子汉一样顶天立地，勇于抗争。

unwillingly

--

例句
My beard had started to grow, and I had unwillingly complied with the order to shave it off.
我的胡子开始长出来，而我不得不服从命令把胡子刮掉。

grudgingly

ADJ-GRADED 勉强的；不情愿的；

例句
The hallowed portals of academe were slowly and grudgingly opening to women.
大学神圣的大门缓慢又勉强地向女性敞开。

consented

v. 同意( consent的过去式和过去分词 )，赞成，允许，顺从；

例句
He finally consented to go...
他最终同意去了。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

marriage

n. 结婚，婚姻生活，密切结合，合并；

例句
Rosie's idyllic world came to an abrupt end when her parents' marriage broke up...
父母婚姻的破裂使得罗茜田园诗般美好的世界陡然画上了句号。