She received the news with apparent unconcern.

她接到这消息时显然无动于衷。

《牛津词典》

'Well, I can't mind the exact day without looking at my memorandum-book, ' replied Crick, with the same intolerable unconcern.

“啊，我要看看我的备忘录，不然我不记得准确的日子，”克里克回答说，说话里同样带着叫人无法忍受的漠不关心。

youdao

You will go down slow, sir, I suppose?' she said with attempted unconcern.

我想下山时你会慢些走吧，先生？

youdao

"He seems to view with blithe unconcern the erosion of Britain's sovereignty in Europe, " she said, adding that his leadership would put Europe "at the forefront of politics".

BBC: Thatcher and her tussles with Europe