Formulate chord combinations to increase the harmonic complexity of the specified musical excerpt.
|:"^A" F/G/ | ABA AFA | d2 d dcB | ABA AGF | EGF EFG | ABA AFA | 
 d2 d def | gfg eag | fdd d2 :|  
X:1
L:1/8
M:6/8
K:D
|:"^A" F/G/ |"D" ABA AFA |"D" d2 d"G" dcB |"D" ABA"Bm" AGF |"Em" EGF"A7" EFG |"D" ABA AFA | 
"D" d2 d def |"G" gfg"A7" eag |"D" fdd d2 :|  