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