Comment on the hadronic decay of excited heavy quarkonia

We make comments on ref.[Z.Phys. C73, 541 (1997)], and provide partial wave analysis to the decays of excited heavy S-wave $1^{-}$ quarkonia into the basic $1^{-}$ quarkonia state plus $\pi \pi$. It is revealed that there exist contributions of D-wave transition in ${\psi }^{\mathrm{\prime }}⟶J\mathrm{/}\psi \pi \pi$, $\mathrm{{\rm Y}}(2S)⟶\mathrm{{\rm Y}}(1S)\pi \pi$ and $\mathrm{{\rm Y}}(3S)⟶\mathrm{{\rm Y}}(1S)\pi \pi$ by using the data-fitting results in ref.[Z.Phys C73, 541 (1997)]. A possible experimental method to measure the D-wave directly is discussed.