保持低调的英文表达是 "keep a low profile"。这个短语的来源可能是由于人们普遍认为，在社交场合中或者在公共媒体上过多地展示自己会显得自负或者是在某种程度上危害到自己的利益。因此，保持低调就成为了一种优雅和谦虚的表现方式。

下面是一些例句：

He's always been the type to keep a low profile, so it's no surprise that he's been able to avoid the spotlight for so long.

The company decided to keep a low profile during the negotiations in order to avoid drawing unwanted attention to themselves.

Despite her many accomplishments, she always manages to keep a low profile and avoid drawing too much attention to herself.

中文翻译：

他一直都是个低调的人，所以不足为奇的是他一直都能避免公众的注意。

公司决定在谈判中保持低调，以避免引起不必要的关注。

尽管她有很多成就，但她总是能够保持低调，避免引起太多的关注。