Thanks for the reviewer’s comment. The introduction has been revised carefully, including using up-to-date references. For example, the outdated references have been removed. Meanwhile, the articles published within the last two years were added, such as (the Reference2 Yu et al., 2020) and (the Reference21 Tang et al., 2018).
Introduction section must be written on more quality way, i.e., more up-to-date references addressed. Please target the specific gap such as 2015-2021 etc.