Chapter 7 - Complementiser Phrases(69) CP
DP C'
who 2 C IP
met 1 DP I'
t 2 I VP
t 1 you
As a structure this is straightforward. It contains a wh-element in the specifier of CP so
that the whole clause can be interpreted as an interrogative. Moreover it has something
in the C position for the wh-element to agree with. If we accept this as basically correct,
we then have (68a) to account for: why can the verb not move to C when anything but
the subject moves to spec CP? The answer would appear to have to do with the
subject: when this does not move to spec CP the main verb cannot move past I.
We have seen restrictions like this before. The adverb, for example must be above
the verb and the negation must be above the verb but below the tense. It seems that the
verb must be below the subject and hence when the subject is in spec IP the verb can
be no higher than I. However, when the subject moves to spec CP the verb can move
to C and still remain lower than the subject. When the verb cannot move from I to C
there is no choice other than to insert the auxiliary do. However, it appears that the
dummy auxiliary is not enough by itself to provide the wh-element with something to
agree with, thus the auxiliary must be inserted in to tense and move from there to I and
from there to C to provide enough semantic content to support the agreement. The verb
stays behind in the VP:
(70) CP
wh C'
C IP
DP I'
I vP
v'
v VP
V'
V
do