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