I could memorize you could memorize he could memorize we could memorize you could memorize they could memorize
V-ing form
I could be memorizing you could be memorizing he could be memorizing we could be memorizing you could be memorizing they could be memorizing
Perfect
I could have memorized you could have memorized he could have memorized we could have memorized you could have memorized they could have memorized
V-ing perfect
I could have been memorizing you could have been memorizing he could have been memorizing we could have been memorizing you could have been memorizing they could have been memorizing
Negation
Simple form
I could not memorize you could not memorize he could not memorize we could not memorize you could not memorize they could not memorize
V-ing form
I could not be memorizing you could not be memorizing he could not be memorizing we could not be memorizing you could not be memorizing they could not be memorizing
Perfect
I could not have memorized you could not have memorized he could not have memorized we could not have memorized you could not have memorized they could not have memorized
V-ing perfect
I could not have been memorizing you could not have been memorizing he could not have been memorizing we could not have been memorizing you could not have been memorizing they could not have been memorizing
Interrogative form
Simple form
could I memorize? could you memorize? could he memorize? could we memorize? could you memorize? could they memorize?
V-ing form
could I be memorizing? could you be memorizing? could he be memorizing? could we be memorizing? could you be memorizing? could they be memorizing?
Perfect
could I have memorized? could you have memorized? could he have memorized? could we have memorized? could you have memorized? could they have memorized?
V-ing perfect
could I have been memorizing? could you have been memorizing? could he have been memorizing? could we have been memorizing? could you have been memorizing? could they have been memorizing?
Interro-negative form
Simple form
could I not memorize? could you not memorize? could he not memorize? could we not memorize? could you not memorize? could they not memorize?
V-ing form
could I not be memorizing? could you not be memorizing? could he not be memorizing? could we not be memorizing? could you not be memorizing? could they not be memorizing?
Perfect
could I not have memorized? could you not have memorized? could he not have memorized? could we not have memorized? could you not have memorized? could they not have memorized?
V-ing perfect
could I not have been memorizing? could you not have been memorizing? could he not have been memorizing? could we not have been memorizing? could you not have been memorizing? could they not have been memorizing?