http://www.musicnotes.com/id%3Dgglprdsrch&url%3Dhttp://www.musicnotes.com/sheetmusic/mtd.asp?ppn=MN0145612&cmp&gclid=CKXT8Pz-pM4CFckkhgod38YKRw&ca=0&cmpid=pad_roigoogleshopping&utm_source=pad_roigoogleshopping&utm_medium=campaign

这个Solveig's song 明白标的是Am。

小天鹅有C、G、D、A各种key，但明显听着是小调。下面这个
中文版的也标的是Am：

https://www.google.com/search?q=four+little+swans+sheet+music&biw=784&bih=436&tbm=isch&imgil=8kBwxZJH7R783M%253A%253BrQ8aMb_jadhgBM%253Bhttp%25253A%25252F%25252Fwww.everyonepiano.com%25252FMusic-53-Danse-des-petits-cygnes-Dance-of-the-Little-Swans.html&source=iu&pf=m&fir=8kBwxZJH7R783M%253A%252CrQ8aMb_jadhgBM%252C_&usg=__L7E5wbVO6ObKLrScKYX36jVAUsM%3D&dpr=1.5&ved=0ahUKEwiI_Pnw-aTOAhWLFj4KHa3sB1IQyjcIOg&ei=8ruhV4i7NIut-AGt2Z-QBQ#imgrc=8kBwxZJH7R783M%3A