"What do you think of that, Watson?" cried Holmes in high glee, rubbing his hands together with satisfaction. "Don't you think that is an admirable sentiment?"
Dr. Mortimer looked at Holmes with an air ofprofessional interest, and Sir Henry Baskerville turned a pair of puzzled dark eyes upon me.
"I don't know much about the tariff and things of that kind," said he; "but it seems to me we've got a bit off the trail so far as that note is concerned."
「你認為怎樣？華生，你不覺得這是極好的觀點嗎？」福爾摩斯以高興的語調大聲說道，一邊滿足地搓著雙手。
莫提默醫生帶著職業性的興趣看著福爾摩斯，亨利·巴斯克維爾則長著一對困惑的黑眼睛望著我。
「我不太清楚關稅那一類的事，」他說，「但是我覺得我們似乎在談與這封信完全無關的事。」
an air of：這個詞組我們可以把它理解為「處於一種……的氛圍或氣氛當中」。
air做「空氣」講時是不可數名詞。做「氣氛」講時，強調一個整體環境，則是可數名詞。
例如：
There was an air of expectancy among the waiting crowd.
等待的人群有一種期盼的心情。
Slowly, with an air of amusement, he nodded.
他慢慢地點頭，一副饒有興味的神態。
"DO YOU KNOW WHO I AM? " the student asked again. "No, and I don't care, " replied the professor with an air of superiority.
「你知道我是誰嗎？」學生再次問。「不知道，我也不在乎，」教授以居高凌下的語氣回答。
英語當中的靈活用法很多，我們翻譯時也要根據上下文靈活使用。