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