English verb conjugation
COULD MEMORIZE

Regular verb: memorize - memorized - memorized

Affirmation

Simple form	V-ing form
I could memorize you could memorize she could memorize we could memorize you could memorize they could memorize	I could be memorizing you could be memorizing she could be memorizing we could be memorizing you could be memorizing they could be memorizing
Perfect	V-ing perfect
I could have memorized you could have memorized she could have memorized we could have memorized you could have memorized they could have memorized	I could have been memorizing you could have been memorizing she could have been memorizing we could have been memorizing you could have been memorizing they could have been memorizing

Negation

Simple form	V-ing form
I couldn't memorize you couldn't memorize she couldn't memorize we couldn't memorize you couldn't memorize they couldn't memorize	I couldn't be memorizing you couldn't be memorizing she couldn't be memorizing we couldn't be memorizing you couldn't be memorizing they couldn't be memorizing
Perfect	V-ing perfect
I couldn't have memorized you couldn't have memorized she couldn't have memorized we couldn't have memorized you couldn't have memorized they couldn't have memorized	I couldn't have been memorizing you couldn't have been memorizing she couldn't have been memorizing we couldn't have been memorizing you couldn't have been memorizing they couldn't have been memorizing

Interrogative form

Simple form	V-ing form
could I memorize? could you memorize? could she memorize? could we memorize? could you memorize? could they memorize?	could I be memorizing? could you be memorizing? could she be memorizing? could we be memorizing? could you be memorizing? could they be memorizing?
Perfect	V-ing perfect
could I have memorized? could you have memorized? could she have memorized? could we have memorized? could you have memorized? could they have memorized?	could I have been memorizing? could you have been memorizing? could she have been memorizing? could we have been memorizing? could you have been memorizing? could they have been memorizing?

Interro-negative form

Simple form	V-ing form
couldn't I memorize? couldn't you memorize? couldn't she memorize? couldn't we memorize? couldn't you memorize? couldn't they memorize?	couldn't I be memorizing? couldn't you be memorizing? couldn't she be memorizing? couldn't we be memorizing? couldn't you be memorizing? couldn't they be memorizing?
Perfect	V-ing perfect
couldn't I have memorized? couldn't you have memorized? couldn't she have memorized? couldn't we have memorized? couldn't you have memorized? couldn't they have memorized?	couldn't I have been memorizing? couldn't you have been memorizing? couldn't she have been memorizing? couldn't we have been memorizing? couldn't you have been memorizing? couldn't they have been memorizing?