English verb conjugation
COULD PHOTOSYNTHESIZE

Regular verb: photosynthesize - photosynthesized - photosynthesized

Affirmation

Simple form	V-ing form
I could photosynthesize you could photosynthesize he could photosynthesize we could photosynthesize you could photosynthesize they could photosynthesize	I could be photosynthesizing you could be photosynthesizing he could be photosynthesizing we could be photosynthesizing you could be photosynthesizing they could be photosynthesizing
Perfect	V-ing perfect
I could have photosynthesized you could have photosynthesized he could have photosynthesized we could have photosynthesized you could have photosynthesized they could have photosynthesized	I could have been photosynthesizing you could have been photosynthesizing he could have been photosynthesizing we could have been photosynthesizing you could have been photosynthesizing they could have been photosynthesizing

Negation

Simple form	V-ing form
I could not photosynthesize you could not photosynthesize he could not photosynthesize we could not photosynthesize you could not photosynthesize they could not photosynthesize	I could not be photosynthesizing you could not be photosynthesizing he could not be photosynthesizing we could not be photosynthesizing you could not be photosynthesizing they could not be photosynthesizing
Perfect	V-ing perfect
I could not have photosynthesized you could not have photosynthesized he could not have photosynthesized we could not have photosynthesized you could not have photosynthesized they could not have photosynthesized	I could not have been photosynthesizing you could not have been photosynthesizing he could not have been photosynthesizing we could not have been photosynthesizing you could not have been photosynthesizing they could not have been photosynthesizing

Interrogative form

Simple form	V-ing form
could I photosynthesize? could you photosynthesize? could he photosynthesize? could we photosynthesize? could you photosynthesize? could they photosynthesize?	could I be photosynthesizing? could you be photosynthesizing? could he be photosynthesizing? could we be photosynthesizing? could you be photosynthesizing? could they be photosynthesizing?
Perfect	V-ing perfect
could I have photosynthesized? could you have photosynthesized? could he have photosynthesized? could we have photosynthesized? could you have photosynthesized? could they have photosynthesized?	could I have been photosynthesizing? could you have been photosynthesizing? could he have been photosynthesizing? could we have been photosynthesizing? could you have been photosynthesizing? could they have been photosynthesizing?

Interro-negative form

Simple form	V-ing form
could I not photosynthesize? could you not photosynthesize? could he not photosynthesize? could we not photosynthesize? could you not photosynthesize? could they not photosynthesize?	could I not be photosynthesizing? could you not be photosynthesizing? could he not be photosynthesizing? could we not be photosynthesizing? could you not be photosynthesizing? could they not be photosynthesizing?
Perfect	V-ing perfect
could I not have photosynthesized? could you not have photosynthesized? could he not have photosynthesized? could we not have photosynthesized? could you not have photosynthesized? could they not have photosynthesized?	could I not have been photosynthesizing? could you not have been photosynthesizing? could he not have been photosynthesizing? could we not have been photosynthesizing? could you not have been photosynthesizing? could they not have been photosynthesizing?