在线网站下载工具：
工具受到各种打击会不定期失效，免费工具网站注意分辨隐藏广告！
https://keepv.id/31/
https://videodownloaderpro.net/en1/youtube-downloader
https://downloadit.online/youtube-downloader
https://ssyoutube.com/
www.ssemble.com/en4/youtube-downloader/
https://wave.video/convert/youtube-to-mp4-305
https://10downloader.com/en/116
https://en.savefrom.net/1-youtube-video-downloader-533nN/
https://www.ytbvideoly.com/d47-home/