The purpose of this paper is to present constraints on English pre-verbal adjuncts. HPSG assumes that the mapping between argument structure and valence is defined by realization constraints which are satisfied by all lexical heads. To analyze participial constructions which are one type of adjuncts, this paper makes use of the association between argument structure and dependents of lexical heads. Bouma, Gosse, Rob Malouf, and Ivan A. Sag (2001) suggested Argument Structure Extension to present a unified feature-based theory of complement, adjunct, and subject extraction. However, the constraints suggested by above mentioned authors are not proper to explain pre-verbal adjuncts. Therefore this paper suggests Revised Argument Structure Extension for the analysis of pre-verbal adjuncts. Based on Revised Argument Structure Extension, pre-verbal Adjunct structures which modify main clauses can be associated with the main clauses. Furthermore, with recent developments in HPSG, ARG-ST and passive verb lexeme, Revised Argument Structure Extension makes it possible to analyze participial constructions which contain binding relation, passive construction.