https://www.grammarly.com/ www.gingersoftware.com/ http://www.1checker.com/ https://github.com/textlint/textlint https://www.zhihu.com/question/34147404 http://lang-8.com/ http://dict.cnki.net/ utensil commented at 2016-06-07 03:19: http://linggle.com/ http://www.netspeak.org/ http://www.thesaurus.net/