Construct a harmonious chain of chord progressions that enhance the presented musical piece.
|: Bc | (3d^cd (3ed^c d=cBc | dgba g2 d^d | e^def gfg^g | agfe d2 Bc | 
 (3d^cd (3ed^c dcBc | dgba g2 d^d | eceg fdfa | g2 d2 G2 :| |: gf | 
 E^DEF GFGA | (3B^AB gf d3 f | gceg dGBd | age_e d2 ^d2 | eGce dGBd | 
 cBAG A2 Bc | (3d^cd (3ed^c dc (3Bcd | eg fa g2 :|  
X:1
L:1/8
M:2/2
K:G
 |: Bc |"G" (3d^cd (3ed^c d=cBc |"C" dgba g2 d^d |"C" e^def gfg^g |"D7" agfe d2 Bc | 
"G" (3d^cd (3ed^c dcBc |"G" dgba g2 d^d |"C" eceg"D7" fdfa |"G" g2 d2 G2 :| |: gf | 
"Em" E^DEF GFGA |"Em" (3B^AB gf d3 f |"C" gceg"G" dGBd |"Am" age_e d2 ^d2 |"C" eGce"G" dGBd | 
"Am" cBAG A2 Bc |"G" (3d^cd (3ed^c dc (3Bcd |"C" eg"D7" fa"G" g2 :|  