I could smell you could smell she could smell we could smell you could smell they could smell
V-ing form
I could be smelling you could be smelling she could be smelling we could be smelling you could be smelling they could be smelling
Perfect
I could have smelled, smelt you could have smelled, smelt she could have smelled, smelt we could have smelled, smelt you could have smelled, smelt they could have smelled, smelt
V-ing perfect
I could have been smelling you could have been smelling she could have been smelling we could have been smelling you could have been smelling they could have been smelling
Negation
Simple form
I couldn't smell you couldn't smell she couldn't smell we couldn't smell you couldn't smell they couldn't smell
V-ing form
I couldn't be smelling you couldn't be smelling she couldn't be smelling we couldn't be smelling you couldn't be smelling they couldn't be smelling
Perfect
I couldn't have smelled, smelt you couldn't have smelled, smelt she couldn't have smelled, smelt we couldn't have smelled, smelt you couldn't have smelled, smelt they couldn't have smelled, smelt
V-ing perfect
I couldn't have been smelling you couldn't have been smelling she couldn't have been smelling we couldn't have been smelling you couldn't have been smelling they couldn't have been smelling
Interrogative form
Simple form
could I smell? could you smell? could she smell? could we smell? could you smell? could they smell?
V-ing form
could I be smelling? could you be smelling? could she be smelling? could we be smelling? could you be smelling? could they be smelling?
Perfect
could I have smelled, smelt? could you have smelled, smelt? could she have smelled, smelt? could we have smelled, smelt? could you have smelled, smelt? could they have smelled, smelt?
V-ing perfect
could I have been smelling? could you have been smelling? could she have been smelling? could we have been smelling? could you have been smelling? could they have been smelling?
Interro-negative form
Simple form
couldn't I smell? couldn't you smell? couldn't she smell? couldn't we smell? couldn't you smell? couldn't they smell?
V-ing form
couldn't I be smelling? couldn't you be smelling? couldn't she be smelling? couldn't we be smelling? couldn't you be smelling? couldn't they be smelling?
Perfect
couldn't I have smelled, smelt? couldn't you have smelled, smelt? couldn't she have smelled, smelt? couldn't we have smelled, smelt? couldn't you have smelled, smelt? couldn't they have smelled, smelt?
V-ing perfect
couldn't I have been smelling? couldn't you have been smelling? couldn't she have been smelling? couldn't we have been smelling? couldn't you have been smelling? couldn't they have been smelling?