很抱歉第一轮的修改没能解决引言部分的问题。实际上，我们在上一次的修改中

Sorry modify the first round failed to solve the problem of introduction. In fact, we have in the last modification will examine the issue at the beginning of the penultimate paragraph of the article. We submitted two versions: with traces of revision and acceptance of the revised version, but in return, we are based on the number of lines provided with a revised version of the traces, so you can not find our research questions.

I'm sorry that the first round of changes didn't solve the problem in the introduction. In fact, we put the study question at the beginning of the penultimate paragraph of the article in our last revision. We submitted two versions: the revised version with the revision trace and the acceptance version, but in the reply, we provided the number of lines based on the version with revision traces, so you can't find our research question.

I'm sorry that the first round of revision didn't solve the problem of the introduction. In fact, we put the research question at the beginning of the penultimate paragraph in the last revision. We submitted two versions: the one with revision marks and the one after accepting the revision, but in the reply, we provided the number of lines according to the version with revision marks, so you can't find our research problem.<br>