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 couldn't photosynthesize you couldn't photosynthesize he couldn't photosynthesize we couldn't photosynthesize you couldn't photosynthesize they couldn't photosynthesize	I couldn't be photosynthesizing you couldn't be photosynthesizing he couldn't be photosynthesizing we couldn't be photosynthesizing you couldn't be photosynthesizing they couldn't be photosynthesizing
Perfect	V-ing perfect
I couldn't have photosynthesized you couldn't have photosynthesized he couldn't have photosynthesized we couldn't have photosynthesized you couldn't have photosynthesized they couldn't have photosynthesized	I couldn't have been photosynthesizing you couldn't have been photosynthesizing he couldn't have been photosynthesizing we couldn't have been photosynthesizing you couldn't have been photosynthesizing they couldn't 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
couldn't I photosynthesize? couldn't you photosynthesize? couldn't he photosynthesize? couldn't we photosynthesize? couldn't you photosynthesize? couldn't they photosynthesize?	couldn't I be photosynthesizing? couldn't you be photosynthesizing? couldn't he be photosynthesizing? couldn't we be photosynthesizing? couldn't you be photosynthesizing? couldn't they be photosynthesizing?
Perfect	V-ing perfect
couldn't I have photosynthesized? couldn't you have photosynthesized? couldn't he have photosynthesized? couldn't we have photosynthesized? couldn't you have photosynthesized? couldn't they have photosynthesized?	couldn't I have been photosynthesizing? couldn't you have been photosynthesizing? couldn't he have been photosynthesizing? couldn't we have been photosynthesizing? couldn't you have been photosynthesizing? couldn't they have been photosynthesizing?