(0.25)^(1/2)×(-1/27)^(-2/3)=(1/4)^(1/2)×(-1/27)^(-2/3)=[(1/2)^2]^1/2×[（-1/3）^3]^(-2/3)=(1/2)^(2×1/2)×(-1/3)^(-3*2/3)=1/2×(-1/3)^(-2)=1/2×1/(-1/3)^2=1/2×1/(1/9)=1/2×9=9/2