English verb conjugation
COULD SUMMARIZE

Regular verb: summarize - summarized - summarized

Affirmation

Simple form	V-ing form
I could summarize you could summarize he could summarize we could summarize you could summarize they could summarize	I could be summarizing you could be summarizing he could be summarizing we could be summarizing you could be summarizing they could be summarizing
Perfect	V-ing perfect
I could have summarized you could have summarized he could have summarized we could have summarized you could have summarized they could have summarized	I could have been summarizing you could have been summarizing he could have been summarizing we could have been summarizing you could have been summarizing they could have been summarizing

Negation

Simple form	V-ing form
I couldn't summarize you couldn't summarize he couldn't summarize we couldn't summarize you couldn't summarize they couldn't summarize	I couldn't be summarizing you couldn't be summarizing he couldn't be summarizing we couldn't be summarizing you couldn't be summarizing they couldn't be summarizing
Perfect	V-ing perfect
I couldn't have summarized you couldn't have summarized he couldn't have summarized we couldn't have summarized you couldn't have summarized they couldn't have summarized	I couldn't have been summarizing you couldn't have been summarizing he couldn't have been summarizing we couldn't have been summarizing you couldn't have been summarizing they couldn't have been summarizing

Interrogative form

Simple form	V-ing form
could I summarize? could you summarize? could he summarize? could we summarize? could you summarize? could they summarize?	could I be summarizing? could you be summarizing? could he be summarizing? could we be summarizing? could you be summarizing? could they be summarizing?
Perfect	V-ing perfect
could I have summarized? could you have summarized? could he have summarized? could we have summarized? could you have summarized? could they have summarized?	could I have been summarizing? could you have been summarizing? could he have been summarizing? could we have been summarizing? could you have been summarizing? could they have been summarizing?

Interro-negative form

Simple form	V-ing form
couldn't I summarize? couldn't you summarize? couldn't he summarize? couldn't we summarize? couldn't you summarize? couldn't they summarize?	couldn't I be summarizing? couldn't you be summarizing? couldn't he be summarizing? couldn't we be summarizing? couldn't you be summarizing? couldn't they be summarizing?
Perfect	V-ing perfect
couldn't I have summarized? couldn't you have summarized? couldn't he have summarized? couldn't we have summarized? couldn't you have summarized? couldn't they have summarized?	couldn't I have been summarizing? couldn't you have been summarizing? couldn't he have been summarizing? couldn't we have been summarizing? couldn't you have been summarizing? couldn't they have been summarizing?