Referencing Column List For Foreign Key No Match

I'm encountering this very weird problem, so I create a staff table:

CREATE TABLE Staff (
staffNo numeric(10),
venueNo numeric(10),
name nvarchar(20),
DOB datetime,
position nvarchar(20),
salary numeric(8,2)
CONSTRAINT staff_PK PRIMARY KEY(staffNo, venueNo),
CONSTRAINT venue_FK FOREIGN KEY(venueNo) REFERENCES Venue
);

and then when I create a professional therapist table

CREATE TABLE Professional_Therapist (
staffNo numeric(10),
specialization nvarchar(20),
bonus numeric(8,2),
CONSTRAINT professional_PK PRIMARY KEY(staffNo),
CONSTRAINT staff_FK FOREIGN KEY(staffNo) REFERENCES Staff
);

It says : The number of columns in the referencing column list for foreign key 'staff_fk' does not match those of the primary key in the referenced table 'Staff'.