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