$-$      $0.0205$          $-$          $-$        $-$      $0.0116$
   $\varepsilon(\Omega_{\rm m})$     $0.0088$     $0.0102$   $0.0125$   $0.0097$        $0.0034$     $0.0040$   $0.0054$   $0.0081$
      $\varepsilon(\emph{h})$        $0.0035$     $0.0075$   $0.0076$   $0.0037$        $0.0018$     $0.0037$   $0.0047$   $0.0025$
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We constrain the $\Lambda$CDM, $w$CDM, CPL and HDE models by using the data combinations of SN+CMB+BAO, SN+CMB+BAO+E-ELT, SN+CMB+BAO+E-ELT+SKA1, and SN+CMB+BAO+E-ELT+SKA2 to complete our analysis. The priors of the free parameters are given in Table \[prior\]. Here, $\Omega_{\rm b}h^{2}$ and $\Omega_{\rm c}h^{2}$ respectively stand for the physical baryon and cold dark matter densities. The constraint results are presented in Tables \[Parameter\]–\[Precision\] and Figs. \[h\]–\[parameters\]. In Table \[Parameter\], we show the best-fit results with the 1$\sigma$ errors quoted. The constraint errors and precisions of the cosmological parameters are given in Tables \[Error\]–\[Precision\], respectively. Here, for a parameter $\xi$, we use $\sigma(\xi)$ to denote its 1$\sigma$ error. For the cases that its distribution slightly deviates from the gaussian distribution, we adopt the value of averaging the upper-limit and lower-limit errors. We use $\varepsilon(\xi)=\sigma(\xi)/\xi_{\rm bf}$ to denote the relative error of the parameter $\xi$, where $\xi_{\rm bf}$ is its best-fit value. In this paper, for convenience, we also informally call $\varepsilon(\xi)$ the “constraint precision” of the parameter $\xi$. In 