I could synthesize you could synthesize he could synthesize we could synthesize you could synthesize they could synthesize
V-ing form
I could be synthesizing you could be synthesizing he could be synthesizing we could be synthesizing you could be synthesizing they could be synthesizing
Perfect
I could have synthesized you could have synthesized he could have synthesized we could have synthesized you could have synthesized they could have synthesized
V-ing perfect
I could have been synthesizing you could have been synthesizing he could have been synthesizing we could have been synthesizing you could have been synthesizing they could have been synthesizing
Negation
Simple form
I couldn't synthesize you couldn't synthesize he couldn't synthesize we couldn't synthesize you couldn't synthesize they couldn't synthesize
V-ing form
I couldn't be synthesizing you couldn't be synthesizing he couldn't be synthesizing we couldn't be synthesizing you couldn't be synthesizing they couldn't be synthesizing
Perfect
I couldn't have synthesized you couldn't have synthesized he couldn't have synthesized we couldn't have synthesized you couldn't have synthesized they couldn't have synthesized
V-ing perfect
I couldn't have been synthesizing you couldn't have been synthesizing he couldn't have been synthesizing we couldn't have been synthesizing you couldn't have been synthesizing they couldn't have been synthesizing
Interrogative form
Simple form
could I synthesize? could you synthesize? could he synthesize? could we synthesize? could you synthesize? could they synthesize?
V-ing form
could I be synthesizing? could you be synthesizing? could he be synthesizing? could we be synthesizing? could you be synthesizing? could they be synthesizing?
Perfect
could I have synthesized? could you have synthesized? could he have synthesized? could we have synthesized? could you have synthesized? could they have synthesized?
V-ing perfect
could I have been synthesizing? could you have been synthesizing? could he have been synthesizing? could we have been synthesizing? could you have been synthesizing? could they have been synthesizing?
Interro-negative form
Simple form
couldn't I synthesize? couldn't you synthesize? couldn't he synthesize? couldn't we synthesize? couldn't you synthesize? couldn't they synthesize?
V-ing form
couldn't I be synthesizing? couldn't you be synthesizing? couldn't he be synthesizing? couldn't we be synthesizing? couldn't you be synthesizing? couldn't they be synthesizing?
Perfect
couldn't I have synthesized? couldn't you have synthesized? couldn't he have synthesized? couldn't we have synthesized? couldn't you have synthesized? couldn't they have synthesized?
V-ing perfect
couldn't I have been synthesizing? couldn't you have been synthesizing? couldn't he have been synthesizing? couldn't we have been synthesizing? couldn't you have been synthesizing? couldn't they have been synthesizing?