Question

the tune of the song of the reaper girl was

Answer 1

This Scottish song was incomprehensible to the poet and yet its melancholic tune touched him deeply. Therefore, the poet kept watching her sing to herself in a distance so as not to disturb her. Wordsworth does not know the reason behind the sad tune but contemplates the loss of a near one, a loss in war or the simple rustic life of the people of the countryside. The theme throughout the whole poem seems to be the beauty of the song, and the lingering effect it leaves upon the poet.

Answer 2

she sang a melancholy strain....