OR logic operator in sparql

Question

I’m trying to build a sparql query using Or, like:

SELECT ?a ?b ?c
WHERE (?a :property ?b **OR** ?b :property ?c **OR** ?a :property ?x OR .....)
...

ms I cannot use, because it throws the following error:

Encountered " "or" "or "" at line 9, column 25.
Was expecting one of: 
...

how can I do it?