Abstract.There is no auxiliary selection rule. ‘Have’ is identical to ‘be’ but for the incorporation of an abstract preposition (cf. Freeze (1992). The alternation is to be understood largely in terms of properties of the participial clause complement‐whether it is full or reduced, whether AGR‐S raises or not, whether Spec, AGR‐O is moved through or not, how many arguments the V has that need to be Case‐licensed. Primarily Romance languages are considered, including a number not traditionally taken int