Download youtube-dl for your system:
http://rg3.github.io/youtube-dl/download.html
...and download using this simple command:
Code:
youtube-dl http://exacdn.edumall.vn/videos/library-kelley-10-07-2016-tuanba.01/ket-thuclibrary-kelley-10-07-2016-tuanba.01/ket-thuc_720_.m3u8 best