表达式45: "G" Subscript, 1 , Baseline equals StartFraction, StartNestedFraction, 1 NestedOver "m" Subscript, 1 , Baseline , EndNestedFraction "H" Subscript, 1 , Baseline plus "H" Subscript, 2 , Baseline plus "m" Subscript, 1 , Baseline "D" Subscript, 1 , Baseline minus "D" Subscript, 2 , Baseline Over "m" Subscript, 1 , Baseline plus StartNestedFraction, 1 NestedOver "m" Subscript, 1 , Baseline , EndNestedFraction , EndFractionG1=1m1H1+H2+m1D1−D2m1+1m1