I could lunch you could lunch she could lunch we could lunch you could lunch they could lunch
V-ing form
I could be lunching you could be lunching she could be lunching we could be lunching you could be lunching they could be lunching
Perfect
I could have lunched you could have lunched she 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 she 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 she 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 she 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 she 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 she 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 she lunch? could we lunch? could you lunch? could they lunch?
V-ing form
could I be lunching? could you be lunching? could she be lunching? could we be lunching? could you be lunching? could they be lunching?
Perfect
could I have lunched? could you have lunched? could she 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 she 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 she 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 she 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 she 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 she have been lunching? couldn't we have been lunching? couldn't you have been lunching? couldn't they have been lunching?