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