"What d'you think?" she asked in an undertone.

“你觉得呢？”她低声问。

《柯林斯英汉双解大词典》

He added in an undertone to the Queen, "Really, my dear, YOU must cross-examine the next witness."

他又低声对王后说：“真的，亲爱的，下一个证人必须你来盘问了。”

youdao

Mammon in English holds a meaning of "wealth" or "possessions" but with a negative undertone.

Mammon在英语里有着“财富”或者“财产”的意思，不过却带有贬义。

youdao

In my first example, I will use the sarcastic undertone.

在第一个例句中，我会带点挖苦的意思。

Do you ever课堂 - SpeakingMax英语口语达人

In the next example, let's try using the "Do you ever" pattern without the sarcastic undertone.

在下一个例句中，“Do you ever”并不带挖苦的意思。

Do you ever课堂 - SpeakingMax英语口语达人

And there's starting to be a little bit of an undertone of that in this conversation.

NPR: Should Detroit Bail Out By Selling Van Gogh?

"This has nothing to do with politics other than everything that's done in Washington has a political undertone to it, " he says, noting that constituents are demanding answers from lawmakers on energy concerns.

FORBES: Election-Year Energy

In particular, Mr Netanyahu and his friends in the pro-Israel lobby in the United States are inveighing vehemently, albeit with an undertone of panic, against the campaign by the Palestinians to win a vote in the UN later this month to grant them statehood, at least on paper.

ECONOMIST: Egypt and Israel