I could sandwich you could sandwich he could sandwich we could sandwich you could sandwich they could sandwich
V-ing form
I could be sandwiching you could be sandwiching he could be sandwiching we could be sandwiching you could be sandwiching they could be sandwiching
Perfect
I could have sandwiched you could have sandwiched he could have sandwiched we could have sandwiched you could have sandwiched they could have sandwiched
V-ing perfect
I could have been sandwiching you could have been sandwiching he could have been sandwiching we could have been sandwiching you could have been sandwiching they could have been sandwiching
Negation
Simple form
I couldn't sandwich you couldn't sandwich he couldn't sandwich we couldn't sandwich you couldn't sandwich they couldn't sandwich
V-ing form
I couldn't be sandwiching you couldn't be sandwiching he couldn't be sandwiching we couldn't be sandwiching you couldn't be sandwiching they couldn't be sandwiching
Perfect
I couldn't have sandwiched you couldn't have sandwiched he couldn't have sandwiched we couldn't have sandwiched you couldn't have sandwiched they couldn't have sandwiched
V-ing perfect
I couldn't have been sandwiching you couldn't have been sandwiching he couldn't have been sandwiching we couldn't have been sandwiching you couldn't have been sandwiching they couldn't have been sandwiching
Interrogative form
Simple form
could I sandwich? could you sandwich? could he sandwich? could we sandwich? could you sandwich? could they sandwich?
V-ing form
could I be sandwiching? could you be sandwiching? could he be sandwiching? could we be sandwiching? could you be sandwiching? could they be sandwiching?
Perfect
could I have sandwiched? could you have sandwiched? could he have sandwiched? could we have sandwiched? could you have sandwiched? could they have sandwiched?
V-ing perfect
could I have been sandwiching? could you have been sandwiching? could he have been sandwiching? could we have been sandwiching? could you have been sandwiching? could they have been sandwiching?
Interro-negative form
Simple form
couldn't I sandwich? couldn't you sandwich? couldn't he sandwich? couldn't we sandwich? couldn't you sandwich? couldn't they sandwich?
V-ing form
couldn't I be sandwiching? couldn't you be sandwiching? couldn't he be sandwiching? couldn't we be sandwiching? couldn't you be sandwiching? couldn't they be sandwiching?
Perfect
couldn't I have sandwiched? couldn't you have sandwiched? couldn't he have sandwiched? couldn't we have sandwiched? couldn't you have sandwiched? couldn't they have sandwiched?
V-ing perfect
couldn't I have been sandwiching? couldn't you have been sandwiching? couldn't he have been sandwiching? couldn't we have been sandwiching? couldn't you have been sandwiching? couldn't they have been sandwiching?