English verb conjugation
COULD SHELVE

Regular verb: shelve - shelved - shelved

Affirmation

Simple form	V-ing form
I could shelve you could shelve he could shelve we could shelve you could shelve they could shelve	I could be shelving you could be shelving he could be shelving we could be shelving you could be shelving they could be shelving
Perfect	V-ing perfect
I could have shelved you could have shelved he could have shelved we could have shelved you could have shelved they could have shelved	I could have been shelving you could have been shelving he could have been shelving we could have been shelving you could have been shelving they could have been shelving

Negation

Simple form	V-ing form
I could not shelve you could not shelve he could not shelve we could not shelve you could not shelve they could not shelve	I could not be shelving you could not be shelving he could not be shelving we could not be shelving you could not be shelving they could not be shelving
Perfect	V-ing perfect
I could not have shelved you could not have shelved he could not have shelved we could not have shelved you could not have shelved they could not have shelved	I could not have been shelving you could not have been shelving he could not have been shelving we could not have been shelving you could not have been shelving they could not have been shelving

Interrogative form

Simple form	V-ing form
could I shelve? could you shelve? could he shelve? could we shelve? could you shelve? could they shelve?	could I be shelving? could you be shelving? could he be shelving? could we be shelving? could you be shelving? could they be shelving?
Perfect	V-ing perfect
could I have shelved? could you have shelved? could he have shelved? could we have shelved? could you have shelved? could they have shelved?	could I have been shelving? could you have been shelving? could he have been shelving? could we have been shelving? could you have been shelving? could they have been shelving?

Interro-negative form

Simple form	V-ing form
could I not shelve? could you not shelve? could he not shelve? could we not shelve? could you not shelve? could they not shelve?	could I not be shelving? could you not be shelving? could he not be shelving? could we not be shelving? could you not be shelving? could they not be shelving?
Perfect	V-ing perfect
could I not have shelved? could you not have shelved? could he not have shelved? could we not have shelved? could you not have shelved? could they not have shelved?	could I not have been shelving? could you not have been shelving? could he not have been shelving? could we not have been shelving? could you not have been shelving? could they not have been shelving?