Jeong - s il Song . 2002. T he Struc ture of Eng lish Imperativ e s . S t ud ie s in M od e rn Gramma r 27, 57 - 76 . English imperatives have idiosyncracies that we cannot find in the other types of sentences . First , they usually have covert subjects and always take bare verbs . Second, they never undergo verb raising, that is, even if they have an auxiliary be or have, they need do- support . Third, when they have the overt subject you, the idiosyncracy is more peculiar : the only word order allowed is (Don 't) y ou V X . This study explains the first idiosyncracy by the fact that English imperatives are tenseless . Being tenseless requires no EPP effect, thus allowing covert subject s. Being tenseless also allows bare verbs. The second idiosyncracy is explained by assuming that the auxiliaries be and have, when they are used in the imperative, come to have some meaning related with action. This action- related meaning is incorporated structurally into ActP, a new shell structure right over v/VP . The third idiosyncracy is explained by assuming that the subject , overt or covert, is realized in the Spec of ActP.