I could steam you could steam she could steam we could steam you could steam they could steam
V-ing form
I could be steaming you could be steaming she could be steaming we could be steaming you could be steaming they could be steaming
Perfect
I could have steamed you could have steamed she 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 she could have been steaming we could have been steaming you could have been steaming they could have been steaming
Negation
Simple form
I could not steam you could not steam she could not steam we could not steam you could not steam they could not steam
V-ing form
I could not be steaming you could not be steaming she could not be steaming we could not be steaming you could not be steaming they could not be steaming
Perfect
I could not have steamed you could not have steamed she could not have steamed we could not have steamed you could not have steamed they could not have steamed
V-ing perfect
I could not have been steaming you could not have been steaming she could not have been steaming we could not have been steaming you could not have been steaming they could not have been steaming
Interrogative form
Simple form
could I steam? could you steam? could she steam? could we steam? could you steam? could they steam?
V-ing form
could I be steaming? could you be steaming? could she be steaming? could we be steaming? could you be steaming? could they be steaming?
Perfect
could I have steamed? could you have steamed? could she 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 she have been steaming? could we have been steaming? could you have been steaming? could they have been steaming?
Interro-negative form
Simple form
could I not steam? could you not steam? could she not steam? could we not steam? could you not steam? could they not steam?
V-ing form
could I not be steaming? could you not be steaming? could she not be steaming? could we not be steaming? could you not be steaming? could they not be steaming?
Perfect
could I not have steamed? could you not have steamed? could she not have steamed? could we not have steamed? could you not have steamed? could they not have steamed?
V-ing perfect
could I not have been steaming? could you not have been steaming? could she not have been steaming? could we not have been steaming? could you not have been steaming? could they not have been steaming?