“你不明白。”他低声说道。用英语怎么说？

“你不明白。”他低声说道。

"You don't understand," he breathed.

you

pron. 你，你们，您们，各位，大家；

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

understand

vt.& vi. 懂，理解；vt. 了解，默认，听说，领会；

例句
Another accusation levelled at the Minister is that he does not understand ordinary people...
另一个矛头则直指部长不懂得体恤百姓。

he

pron. 他，它，一个人；n. 雄性动物；

例句
Logic had prevailed and he had abandoned the idea.
最终理智占了上风，他打消了那个念头。

breathed

adj. 无声的，有气的；v. 呼吸( breathe的过去式和过去分词 )，轻声说话，低语，低声说；

例句
He never breathed a word about our conversation.
关于我们的谈话他只字未提。