The song of the week is 'Will You Be Loving Another Man' in the key of A.
This classic bluegrass song was written by Bill Monroe and Lester Flatt during WWII, and then recorded after the war in 1946 by the original bluegrass band, Bill Monroe and his Bluegrass Boys, which consisted at the time of Bill Monroe on mandolin, Lester Flatt on guitar, Earl Scruggs on banjo, Chubby Wise on fiddle, and Howard Watts on bass.
Here is the original 1946 recording of Will You Be Loving Another Man, with Lester Flatt on lead vocal and Bill Monroe on harmony vocal during the choruses:
key of A:
The chord progression for Will You Be Loving Another Man is:
(Prog. V2 on the Basic Chord Progressions handout.)
This is the same progression that is used to play Mama Don't Allow, She'll Be Coming Round The Mountain, The Crawdad Song, and When The Saints Go Marching In.
Notice on the recording how each of the breaks differ from each other. The short mandolin intro break (half the length of a full intro break: it uses the last half of the progression) states the melody of the song in a simple manner, making use of drony-sounding double stops in connection with the main melody notes.
In the first fiddle break, there is a lot more going on than what there was in the mandolin intro break, yet the melody is never lost sight of at any point in the break: its influence on the break is there from beginning to end.
The banjo break zeros in on only the most essential notes of the melody and fills up the space between them with 8th notes that, for the most part, are notes that are part of the chord being played at the time.
Finally, the second fiddle break, after its first four measures, contains almost no trace of the melody at all. The last 3/4 of this break is made up entirely of non-melody-based licks (which have gone on to become standard - one might say 'cliche' - bluegrass fiddle licks), fitted to the chord progression of the song.