why do we need to change the past verb to a bare infinity infinitive
in question and negative form |
|
Only one past marker is allowed
within a single clause. The auxiliary takes the past marker, so
the main verb cannot. The regular past marker is
d, but some verbs are irregular, of course. The past marker for
do is
did. The past marker for
go is
went. Since you can't have more than one past marker in the same clause, you can't have both
did and
went in the same clause.
You can express the affirmative forms without an auxiliary, so there
the main verb takes the past marker. It has to; it's the only
verb in the sentence.
He went.
But if you express the affirmative with the auxiliary (the so-called "emphatic" form),
did carries the past marker and so
go cannot.
He did go. (Never
He did went.)
The question and negative forms always use the auxiliary so the main verb can never take the past marker in those cases.
He didn't go. Did he go? Didn't he go?
CJ
For more on grammatical tense markers, see
Post:255817.