English verb conjugation
COULD EXTEND

Regular verb: extend - extended - extended

Affirmation

Simple form	V-ing form
I could extend you could extend he could extend we could extend you could extend they could extend	I could be extending you could be extending he could be extending we could be extending you could be extending they could be extending
Perfect	V-ing perfect
I could have extended you could have extended he could have extended we could have extended you could have extended they could have extended	I could have been extending you could have been extending he could have been extending we could have been extending you could have been extending they could have been extending

Negation

Simple form	V-ing form
I could not extend you could not extend he could not extend we could not extend you could not extend they could not extend	I could not be extending you could not be extending he could not be extending we could not be extending you could not be extending they could not be extending
Perfect	V-ing perfect
I could not have extended you could not have extended he could not have extended we could not have extended you could not have extended they could not have extended	I could not have been extending you could not have been extending he could not have been extending we could not have been extending you could not have been extending they could not have been extending

Interrogative form

Simple form	V-ing form
could I extend? could you extend? could he extend? could we extend? could you extend? could they extend?	could I be extending? could you be extending? could he be extending? could we be extending? could you be extending? could they be extending?
Perfect	V-ing perfect
could I have extended? could you have extended? could he have extended? could we have extended? could you have extended? could they have extended?	could I have been extending? could you have been extending? could he have been extending? could we have been extending? could you have been extending? could they have been extending?

Interro-negative form

Simple form	V-ing form
could I not extend? could you not extend? could he not extend? could we not extend? could you not extend? could they not extend?	could I not be extending? could you not be extending? could he not be extending? could we not be extending? could you not be extending? could they not be extending?
Perfect	V-ing perfect
could I not have extended? could you not have extended? could he not have extended? could we not have extended? could you not have extended? could they not have extended?	could I not have been extending? could you not have been extending? could he not have been extending? could we not have been extending? could you not have been extending? could they not have been extending?