Key signature, one sharp, G major or E minor.

调号，一个升号，G 大调或 E 小调。

Or it could be what's called the relative minor; would be E minor with the same key signature.

或者它可能是所谓的相对未成年人；将是具有相同调号的 E 小调。

The recording was of a piece of classical music: Mendelssohn's Concerto in E minor.

录音是一段古典音乐：门德尔松的 E 小调协奏曲。