Accusative case in passives

The standard explanation for NP movement in the passive construction has been that the NP must move into the nominative position? because no accusative case is available. This paper examines the implications for this view of some double-object constructions in Mandarin Chinese and English that are ungrammatical as active clauses but improve significantly as passives. These facts are unexpected under the standard view of passives, but I suggest that they cart be explained if we assume that the second object is not licensed for case in the active versions but is able to check accusative case in the passive version, thus arguing that accusative case is available in passive clauses.