What is the name of your state or, if not in the US, what is the name of your country? Edit: Never mind. I see from your previous thread that you are located in California.
Anyone who opposes a mark's registration must file his written opposition within 30 days of the mark's proposed publication in the Official Gazette, but the USPTO can grant extensions. Extensions on filing an opposition cannot exceed 180 days.
And, once a mark has been placed on the Principal Register, anyone who opposes the registration can petition the USPTO for cancellation of the registration (within 5 years of publication, upon abandonment, over misuse of mark).