I received comments from two reviewers, both suggested "major revision". Both reviewers pointed out the authors did not clearly present the novelty of their manuscript, compared with previous studies. Both reviewers think there are some issues in the study on the two synthetical cases are not clearly presented. The writing also needs polish.

After receiving the comments, I carefully read the manuscript again, and concur with the reviewers. The authors have also provide their responses to the comments and questions reasonably. Please revise the manuscript according to the comments made by the two reviewers. The revised manuscript will be reviewed again by the two reviewers.

Please submit a revised version based on the reviews submitted on 16 and 23 January.

I received review comments from two reviewers, reviewer 1 suggested "accepted" and reviewer 2 suggested "reject". The reviewer 2 pointed out three aspects should be revised, 1. The writing needed to be significantly polished; 2. The manuscript should be restructured; and 3. the novelty and contributions need to be more clear. He/she also provided the specific comments/questions which needed to be addressed. After receiving the comments, I read your manuscript again and concurred with the reviewer. Therefore, the manuscript needs major revision. The revised version will be reviewed by reviewer 2.

I received comments from two reviewers to the revised manuscript. Both reviewers suggested "publish as is". After receiving the comments, I read the manuscript again, and concurred with the reviewers.