Test your skills
Although YouTube itself doesn't scan the videos users post for copyright infringements (they assume you are the owner of it or you have rights for it; it would be impossible for them to scan each and every video posted from the millions of members the site has) if they receive any notice from the original (that has stumbled upon your video) they will immediately act accordingly and take down your video.
Moreover you will get a strike and your standing as a YouTube member will go down. After several strikes you'll get a ban.
So my suggestion is to upload on YouTube only videos that you posses the rights to. TV serial or movie clippings are prohibited and will be taken down eventually. However you might get away with posting footage from trailers for example. Those are there for advertising anyway.
I hope this helps.
Yes you can as long as the material you are uploading isn’t illegal. And many people do it. If you search for such stuff in YouTube, you can find many more results.
And even if its illegal. its not like its prohibited. You can always upload any video.
Make sure you allow comments to it.