Who vs Whom

Click on the audio to listen to the explanation about the differences between these two pronouns. Also, you have the tapscript on the same page so you can follow the explanation by reading.
http://grammar.quickanddirtytips.com/who-versus-whom.aspx

Furthermore, there is another link to a page where you can find a more in detail exposition on the differences between the two of them:
http://www.elearnenglishlanguage.com/difficulties/whowhom.html
I hope you find it clarifying but if there's still any question, write it down and ask in class!