English verb conjugation
COULD SAP

Regular verb: sap - sapped - sapped

Affirmation

Simple form	V-ing form
I could sap you could sap he could sap we could sap you could sap they could sap	I could be sapping you could be sapping he could be sapping we could be sapping you could be sapping they could be sapping
Perfect	V-ing perfect
I could have sapped you could have sapped he could have sapped we could have sapped you could have sapped they could have sapped	I could have been sapping you could have been sapping he could have been sapping we could have been sapping you could have been sapping they could have been sapping

Negation

Simple form	V-ing form
I couldn't sap you couldn't sap he couldn't sap we couldn't sap you couldn't sap they couldn't sap	I couldn't be sapping you couldn't be sapping he couldn't be sapping we couldn't be sapping you couldn't be sapping they couldn't be sapping
Perfect	V-ing perfect
I couldn't have sapped you couldn't have sapped he couldn't have sapped we couldn't have sapped you couldn't have sapped they couldn't have sapped	I couldn't have been sapping you couldn't have been sapping he couldn't have been sapping we couldn't have been sapping you couldn't have been sapping they couldn't have been sapping

Interrogative form

Simple form	V-ing form
could I sap? could you sap? could he sap? could we sap? could you sap? could they sap?	could I be sapping? could you be sapping? could he be sapping? could we be sapping? could you be sapping? could they be sapping?
Perfect	V-ing perfect
could I have sapped? could you have sapped? could he have sapped? could we have sapped? could you have sapped? could they have sapped?	could I have been sapping? could you have been sapping? could he have been sapping? could we have been sapping? could you have been sapping? could they have been sapping?

Interro-negative form

Simple form	V-ing form
couldn't I sap? couldn't you sap? couldn't he sap? couldn't we sap? couldn't you sap? couldn't they sap?	couldn't I be sapping? couldn't you be sapping? couldn't he be sapping? couldn't we be sapping? couldn't you be sapping? couldn't they be sapping?
Perfect	V-ing perfect
couldn't I have sapped? couldn't you have sapped? couldn't he have sapped? couldn't we have sapped? couldn't you have sapped? couldn't they have sapped?	couldn't I have been sapping? couldn't you have been sapping? couldn't he have been sapping? couldn't we have been sapping? couldn't you have been sapping? couldn't they have been sapping?