5W-EVER

Whatever - Whenever - Wherever - Whichever - Whoever

+ Whatever: anything or everything; regardless of what
   _ Whatever you do, don't forget your grandmother's birthday.
   _ Don't get upset whatever your mother says.

+ Whenever: every time; at any time; ragardless of when
   _ Whenever we organize a picnic it rains.
   _ He interrupts me whenever I start to speak.

+ Wherever: everywhere; no matter where; regardless of where
   _ Wherever you go you'll always find someone who speaks English.
   _ She'll be happy wherever she decides to live

+ Whichever: the peron or thing which; no matter which; regardless of which
   _ Wear whichever shoes are the most comfortable.
   _ Take whichever one you want.

+ Whoever: the person who; regardless of who
   _ Whoever comes with you is welcome.
   _ Whoever opened the gate didn't close it.

Reference: www.vocabularypage.com