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