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