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