Active Directory

I have recently been called for an interview by a IT company, & the HR person said that I will be quized on technical support & Active Directory(utilities & user accounts) topics. Now I applied for this position as a help desk position but now they want me to go through these topics. I am a MCP in Windows 2000 server, workstation, network directories infrastructure & one more(i can't remember). My question is what do I need to study for the Active Directory Quiz that they will give me - I would like a crash course on Active Directory. I have looked at the technet website from microsoft. Any pointers appreciated.