I could alphabetize you could alphabetize she could alphabetize we could alphabetize you could alphabetize they could alphabetize
V-ing form
I could be alphabetizing you could be alphabetizing she could be alphabetizing we could be alphabetizing you could be alphabetizing they could be alphabetizing
Perfect
I could have alphabetized you could have alphabetized she could have alphabetized we could have alphabetized you could have alphabetized they could have alphabetized
V-ing perfect
I could have been alphabetizing you could have been alphabetizing she could have been alphabetizing we could have been alphabetizing you could have been alphabetizing they could have been alphabetizing
Negation
Simple form
I couldn't alphabetize you couldn't alphabetize she couldn't alphabetize we couldn't alphabetize you couldn't alphabetize they couldn't alphabetize
V-ing form
I couldn't be alphabetizing you couldn't be alphabetizing she couldn't be alphabetizing we couldn't be alphabetizing you couldn't be alphabetizing they couldn't be alphabetizing
Perfect
I couldn't have alphabetized you couldn't have alphabetized she couldn't have alphabetized we couldn't have alphabetized you couldn't have alphabetized they couldn't have alphabetized
V-ing perfect
I couldn't have been alphabetizing you couldn't have been alphabetizing she couldn't have been alphabetizing we couldn't have been alphabetizing you couldn't have been alphabetizing they couldn't have been alphabetizing
Interrogative form
Simple form
could I alphabetize? could you alphabetize? could she alphabetize? could we alphabetize? could you alphabetize? could they alphabetize?
V-ing form
could I be alphabetizing? could you be alphabetizing? could she be alphabetizing? could we be alphabetizing? could you be alphabetizing? could they be alphabetizing?
Perfect
could I have alphabetized? could you have alphabetized? could she have alphabetized? could we have alphabetized? could you have alphabetized? could they have alphabetized?
V-ing perfect
could I have been alphabetizing? could you have been alphabetizing? could she have been alphabetizing? could we have been alphabetizing? could you have been alphabetizing? could they have been alphabetizing?
Interro-negative form
Simple form
couldn't I alphabetize? couldn't you alphabetize? couldn't she alphabetize? couldn't we alphabetize? couldn't you alphabetize? couldn't they alphabetize?
V-ing form
couldn't I be alphabetizing? couldn't you be alphabetizing? couldn't she be alphabetizing? couldn't we be alphabetizing? couldn't you be alphabetizing? couldn't they be alphabetizing?
Perfect
couldn't I have alphabetized? couldn't you have alphabetized? couldn't she have alphabetized? couldn't we have alphabetized? couldn't you have alphabetized? couldn't they have alphabetized?
V-ing perfect
couldn't I have been alphabetizing? couldn't you have been alphabetizing? couldn't she have been alphabetizing? couldn't we have been alphabetizing? couldn't you have been alphabetizing? couldn't they have been alphabetizing?