(Course video tutorials. It is said that the open courses of foreign universities that emerged in the past year or two have long been available in China. This is one of them. Hope this can be helpful for our study. As for the player, you need to use a special player. According to the format of the video, just look it up on the Internet. Because there are too many files, the attachments cannot be placed, so I upload a file with a download address in it.)