说明：  LaTeX使用课本，上课用的，哪里不会就自己查查，很好用，省的百度和到处求助，觉得不错，希望对大家有帮助。
(LaTeX use textbooks, classes, and where not to check on their own, very good use of the province of Baidu and everywhere to help, feel good, I hope all of you help.)