Proform test: PPs
Proforms: (replace P')
(i) there and then
(ii) the wh-elements how, when, where, and why
While these may look like PP proforms, their ability to occur with PP specifiers demonstrates that minimally they have P' rather than PP status:
right [P' then/there]
[PP Just [P' where]] did you put the cat?
[PP [P' Where]] did you put the cat?
[PP Just [P' when/why]] did you do that?
[PP [P' When/Why]] did you do that?