I could cumulate you could cumulate she could cumulate we could cumulate you could cumulate they could cumulate
V-ing form
I could be cumulating you could be cumulating she could be cumulating we could be cumulating you could be cumulating they could be cumulating
Perfect
I could have cumulated you could have cumulated she could have cumulated we could have cumulated you could have cumulated they could have cumulated
V-ing perfect
I could have been cumulating you could have been cumulating she could have been cumulating we could have been cumulating you could have been cumulating they could have been cumulating
Negation
Simple form
I couldn't cumulate you couldn't cumulate she couldn't cumulate we couldn't cumulate you couldn't cumulate they couldn't cumulate
V-ing form
I couldn't be cumulating you couldn't be cumulating she couldn't be cumulating we couldn't be cumulating you couldn't be cumulating they couldn't be cumulating
Perfect
I couldn't have cumulated you couldn't have cumulated she couldn't have cumulated we couldn't have cumulated you couldn't have cumulated they couldn't have cumulated
V-ing perfect
I couldn't have been cumulating you couldn't have been cumulating she couldn't have been cumulating we couldn't have been cumulating you couldn't have been cumulating they couldn't have been cumulating
Interrogative form
Simple form
could I cumulate? could you cumulate? could she cumulate? could we cumulate? could you cumulate? could they cumulate?
V-ing form
could I be cumulating? could you be cumulating? could she be cumulating? could we be cumulating? could you be cumulating? could they be cumulating?
Perfect
could I have cumulated? could you have cumulated? could she have cumulated? could we have cumulated? could you have cumulated? could they have cumulated?
V-ing perfect
could I have been cumulating? could you have been cumulating? could she have been cumulating? could we have been cumulating? could you have been cumulating? could they have been cumulating?
Interro-negative form
Simple form
couldn't I cumulate? couldn't you cumulate? couldn't she cumulate? couldn't we cumulate? couldn't you cumulate? couldn't they cumulate?
V-ing form
couldn't I be cumulating? couldn't you be cumulating? couldn't she be cumulating? couldn't we be cumulating? couldn't you be cumulating? couldn't they be cumulating?
Perfect
couldn't I have cumulated? couldn't you have cumulated? couldn't she have cumulated? couldn't we have cumulated? couldn't you have cumulated? couldn't they have cumulated?
V-ing perfect
couldn't I have been cumulating? couldn't you have been cumulating? couldn't she have been cumulating? couldn't we have been cumulating? couldn't you have been cumulating? couldn't they have been cumulating?