and what will happen when the combination of SKA and E-ELT mock data is considered. We use the five data sets, i.e., SKA1, SKA2, E-ELT, E-ELT+SKA1, E-ELT+SKA2, and SN+CMB+BAO to reach our aims in the $\Lambda$CDM model. We find that using the SKA2 mock data alone, the $\Lambda$CDM model can be constrained well, while the constraint is weak from the mock data of SKA1-only. When the redshift drift mock data of SKA and E-ELT are combined, the results show that the parameter space is dramatically reduced almost as good as SN+CMB+BAO. Thus, the last aim of this work is to investigate what role the redshift drift data of SKA will play in constraining dark energy in the future. To fulfill the task, we employ several concrete dark energy models, including the $\Lambda$CDM, $w$CDM, CPL, and HDE models, which are still consistent with the current observations at least to some extent.

We first use the data combination of SN+CMB+BAO to constrain the four dark energy models, and then we consider the addition of the E-ELT mock data in the data combination, i.e., we use the data combination of SN+CMB+BAO+E-ELT to constrain the models. The constraints on cosmological parameters are tremendously improved 