Regular verb: sum - summed - summed
Simple form | V-ing form |
I could sum you could sum he could sum we could sum you could sum they could sum | I could be summing you could be summing he could be summing we could be summing you could be summing they could be summing |
Perfect | V-ing perfect |
I could have summed you could have summed he could have summed we could have summed you could have summed they could have summed | I could have been summing you could have been summing he could have been summing we could have been summing you could have been summing they could have been summing |
Simple form | V-ing form |
I couldn't sum you couldn't sum he couldn't sum we couldn't sum you couldn't sum they couldn't sum | I couldn't be summing you couldn't be summing he couldn't be summing we couldn't be summing you couldn't be summing they couldn't be summing |
Perfect | V-ing perfect |
I couldn't have summed you couldn't have summed he couldn't have summed we couldn't have summed you couldn't have summed they couldn't have summed | I couldn't have been summing you couldn't have been summing he couldn't have been summing we couldn't have been summing you couldn't have been summing they couldn't have been summing |
Simple form | V-ing form |
could I sum? could you sum? could he sum? could we sum? could you sum? could they sum? | could I be summing? could you be summing? could he be summing? could we be summing? could you be summing? could they be summing? |
Perfect | V-ing perfect |
could I have summed? could you have summed? could he have summed? could we have summed? could you have summed? could they have summed? | could I have been summing? could you have been summing? could he have been summing? could we have been summing? could you have been summing? could they have been summing? |
Simple form | V-ing form |
couldn't I sum? couldn't you sum? couldn't he sum? couldn't we sum? couldn't you sum? couldn't they sum? | couldn't I be summing? couldn't you be summing? couldn't he be summing? couldn't we be summing? couldn't you be summing? couldn't they be summing? |
Perfect | V-ing perfect |
couldn't I have summed? couldn't you have summed? couldn't he have summed? couldn't we have summed? couldn't you have summed? couldn't they have summed? | couldn't I have been summing? couldn't you have been summing? couldn't he have been summing? couldn't we have been summing? couldn't you have been summing? couldn't they have been summing? |