-- this is superfluous in gf

VP ::= Have V ;
VP ::= Have V2 NP ;
VP ::= Have Been Comp ;

S  ::= "there" Have Been NP ;
QS ::= Have "there" Been NP ;

Slash ::= NP Have OptAdV V2 ;
Slash ::= NP Have OptAdV VV "to" V2 ;
Slash ::= NP Have Cop OptAdV A2 Prep ;
QS    ::= Have NP Been Comp ;

QS ::= IAdv Mod NP VP ;
QS ::= IAdv Have NP Been ;

IAdv ::= Prep IP ;

-- 

Cop ::= "was" | "were" | "wasn't" | "weren't" ;
Do  ::= "did" | "didn't" ;
Mod ::= "could" | "couldn't" ;

Have ::= "has" | "have" | "had" | "hasn't" | "haven't" | "hadn't" ;
Been ::= "been" ;