Dummy Verbs
isn't, can't, won’t [+V, -N]
[+Main]
[-Main]
[+Modal]
[-Modal]
+V, -N -Main {NULL} [Feature] +Host +V, -N +Main
[{NULL} -> [{BE}] /
[{NULL} -> [{HAVE}] /
Vi0 _____ .... {[+Pass], [+Prog]} +Host +G Vi1 Vi0 _____ .... [+Perf] +Host +G Vi1
Condition: Vio must govern the feature on the right.
