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