beautifully,用副词形式,来修饰动词fly.in the sky是地点状语,无关的.如果是beautifully，in the sky不应该在最后嘛？in the sky是地点状语哦，所以位置可以变化的。你可以说：In the sky, the butterflies are flying beautifully.The butterflies are flying beautifully in the sky.The butterflies are flying in the sky beautifully.