English verb conjugation
COULD LAST

Regular verb: last - lasted - lasted

Affirmation

Simple form	V-ing form
I could last you could last he could last we could last you could last they could last	I could be lasting you could be lasting he could be lasting we could be lasting you could be lasting they could be lasting
Perfect	V-ing perfect
I could have lasted you could have lasted he could have lasted we could have lasted you could have lasted they could have lasted	I could have been lasting you could have been lasting he could have been lasting we could have been lasting you could have been lasting they could have been lasting

Negation

Simple form	V-ing form
I couldn't last you couldn't last he couldn't last we couldn't last you couldn't last they couldn't last	I couldn't be lasting you couldn't be lasting he couldn't be lasting we couldn't be lasting you couldn't be lasting they couldn't be lasting
Perfect	V-ing perfect
I couldn't have lasted you couldn't have lasted he couldn't have lasted we couldn't have lasted you couldn't have lasted they couldn't have lasted	I couldn't have been lasting you couldn't have been lasting he couldn't have been lasting we couldn't have been lasting you couldn't have been lasting they couldn't have been lasting

Interrogative form

Simple form	V-ing form
could I last? could you last? could he last? could we last? could you last? could they last?	could I be lasting? could you be lasting? could he be lasting? could we be lasting? could you be lasting? could they be lasting?
Perfect	V-ing perfect
could I have lasted? could you have lasted? could he have lasted? could we have lasted? could you have lasted? could they have lasted?	could I have been lasting? could you have been lasting? could he have been lasting? could we have been lasting? could you have been lasting? could they have been lasting?

Interro-negative form

Simple form	V-ing form
couldn't I last? couldn't you last? couldn't he last? couldn't we last? couldn't you last? couldn't they last?	couldn't I be lasting? couldn't you be lasting? couldn't he be lasting? couldn't we be lasting? couldn't you be lasting? couldn't they be lasting?
Perfect	V-ing perfect
couldn't I have lasted? couldn't you have lasted? couldn't he have lasted? couldn't we have lasted? couldn't you have lasted? couldn't they have lasted?	couldn't I have been lasting? couldn't you have been lasting? couldn't he have been lasting? couldn't we have been lasting? couldn't you have been lasting? couldn't they have been lasting?