link Download Free youtobe downloader. Once downloaded, open it, copy the link of the video from youtube, paste it there, choose the folder where do 你 want it and that's it!! :)
或者 你 can download this one:
link there is also a program which helps 你 to download only the audio from youtobe (mp3):
link ps: here is a video from youtobe to see how it works :)
link