Relative clauses with who/which

Meaning:

Depend totally on one single person or course of action.

If you put all your eggs into one basket, you put all your energy and time to one thing or purpose. If it fails, you will have no other possibilities left.

Santa Claus is coming to town.

Now, the Special English program, Words and Their Stories. 

(MUSIC)

Our expression today is Santa Claus.  Santa Claus is someone who will remain in the hearts of children forever.  He is the make-believe person who brings toys and other gifts to children at Christmas.