【我愛阿,阿愛我】評論
Trading baseball cards is what I do for a living.=What I do for a living is trading baseball cards.我以買賣棒球卡維生動名詞當主詞視為單數,後接單數動詞,題目中 "Trading baseball cards" 當作一件事,所以動詞接 "is" ; what名詞子句倒裝置於句首當主詞亦視為單數