欢迎来到课程！ 您的视频会自动开始播放，您也可以随时暂停视频，返回时会在同一点开始播放。 您可以通过单击视频右下角的齿轮图标来更改视频质量和速度。

Welcome to the course! Your videos should start playing automatically. You can pause a video at any time and you'll be able to return to the same point in the video. You can change the video quality or speed by clicking on the gear icon at the bottom right of the video.