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 couldn't shelve you couldn't shelve he couldn't shelve we couldn't shelve you couldn't shelve they couldn't shelve	I couldn't be shelving you couldn't be shelving he couldn't be shelving we couldn't be shelving you couldn't be shelving they couldn't be shelving
Perfect	V-ing perfect
I couldn't have shelved you couldn't have shelved he couldn't have shelved we couldn't have shelved you couldn't have shelved they couldn't have shelved	I couldn't have been shelving you couldn't have been shelving he couldn't have been shelving we couldn't have been shelving you couldn't have been shelving they couldn't 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
couldn't I shelve? couldn't you shelve? couldn't he shelve? couldn't we shelve? couldn't you shelve? couldn't they shelve?	couldn't I be shelving? couldn't you be shelving? couldn't he be shelving? couldn't we be shelving? couldn't you be shelving? couldn't they be shelving?
Perfect	V-ing perfect
couldn't I have shelved? couldn't you have shelved? couldn't he have shelved? couldn't we have shelved? couldn't you have shelved? couldn't they have shelved?	couldn't I have been shelving? couldn't you have been shelving? couldn't he have been shelving? couldn't we have been shelving? couldn't you have been shelving? couldn't they have been shelving?