diff bewteen Vtodo with Vevent and VFreeBusy with VJournay?

"陈碧航" <[email protected]> Wed, 10 Mar 2004 14:41:44 +0800
Newsgroups gmane.ietf.calendar
Message-ID <[email protected]>
in the rfc: 
Vevent is an event, Vtodo is a to-do. what's the diff between event and to-do? could u provide me the examples? 
VJournay is a journal entry, VFreeBusy is another thing. if i want to set Monday a free time, and the rest six days are working-day. which component should i implement by this situation? 
i eager to learn it by u guidance.