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