English verb conjugation
COULD PARENTHESIZE

Regular verb: parenthesize - parenthesized - parenthesized

Affirmation

Simple form	V-ing form
I could parenthesize you could parenthesize he could parenthesize we could parenthesize you could parenthesize they could parenthesize	I could be parenthesizing you could be parenthesizing he could be parenthesizing we could be parenthesizing you could be parenthesizing they could be parenthesizing
Perfect	V-ing perfect
I could have parenthesized you could have parenthesized he could have parenthesized we could have parenthesized you could have parenthesized they could have parenthesized	I could have been parenthesizing you could have been parenthesizing he could have been parenthesizing we could have been parenthesizing you could have been parenthesizing they could have been parenthesizing

Negation

Simple form	V-ing form
I couldn't parenthesize you couldn't parenthesize he couldn't parenthesize we couldn't parenthesize you couldn't parenthesize they couldn't parenthesize	I couldn't be parenthesizing you couldn't be parenthesizing he couldn't be parenthesizing we couldn't be parenthesizing you couldn't be parenthesizing they couldn't be parenthesizing
Perfect	V-ing perfect
I couldn't have parenthesized you couldn't have parenthesized he couldn't have parenthesized we couldn't have parenthesized you couldn't have parenthesized they couldn't have parenthesized	I couldn't have been parenthesizing you couldn't have been parenthesizing he couldn't have been parenthesizing we couldn't have been parenthesizing you couldn't have been parenthesizing they couldn't have been parenthesizing

Interrogative form

Simple form	V-ing form
could I parenthesize? could you parenthesize? could he parenthesize? could we parenthesize? could you parenthesize? could they parenthesize?	could I be parenthesizing? could you be parenthesizing? could he be parenthesizing? could we be parenthesizing? could you be parenthesizing? could they be parenthesizing?
Perfect	V-ing perfect
could I have parenthesized? could you have parenthesized? could he have parenthesized? could we have parenthesized? could you have parenthesized? could they have parenthesized?	could I have been parenthesizing? could you have been parenthesizing? could he have been parenthesizing? could we have been parenthesizing? could you have been parenthesizing? could they have been parenthesizing?

Interro-negative form

Simple form	V-ing form
couldn't I parenthesize? couldn't you parenthesize? couldn't he parenthesize? couldn't we parenthesize? couldn't you parenthesize? couldn't they parenthesize?	couldn't I be parenthesizing? couldn't you be parenthesizing? couldn't he be parenthesizing? couldn't we be parenthesizing? couldn't you be parenthesizing? couldn't they be parenthesizing?
Perfect	V-ing perfect
couldn't I have parenthesized? couldn't you have parenthesized? couldn't he have parenthesized? couldn't we have parenthesized? couldn't you have parenthesized? couldn't they have parenthesized?	couldn't I have been parenthesizing? couldn't you have been parenthesizing? couldn't he have been parenthesizing? couldn't we have been parenthesizing? couldn't you have been parenthesizing? couldn't they have been parenthesizing?