--- just one tense considered; no agreement forced

S  ::= NP Do VP ;
S  ::= Adv "," S ;

-- slash category instead of gaps

Slash ::= NP V2 ;
Slash ::= NP VV "to" V2 ;
Slash ::= NP Cop A2 Prep ;
Slash ::= S Prep ;
Slash ::= Slash Adv ; -- who does my son love here

-- questions

QS ::= Do NP VP ;

-- this will be eliminated via richer lintypes
QS ::= Cop NP Comp ;

IntVP.    QS ::= IP VP ;
QS           ::= IP Do VP ;
IntSlash. QS ::= IP Do Slash ;

-- general: QuestAdv : IAdv -> Cl -> QCl ;
QS ::= IAdv Do NP VP ;
QS ::= IAdv Cop NP ;

IAdv ::= "why" | "where" | "when" ;

-- relatives

RelVP. RS ::= RP VP ;
RS ::= RP "doesn't" VP ;
RelSlash. RS ::= RP Slash ;

-- CLE syntax of relatives
NP ::= NP RS ;

IP ::= "who" ;
FunIP. IP ::= "the" N2 "of" IP ;

RP ::= "which" ;
FunRP. RP ::= "the" N2 "of" RP ; -- ?

-- imperative

PosImpVP. Imp ::= VP ;
NegImpVP. Imp ::= "don't" VP ;