I could sadden you could sadden she could sadden we could sadden you could sadden they could sadden
V-ing form
I could be saddening you could be saddening she could be saddening we could be saddening you could be saddening they could be saddening
Perfect
I could have saddened you could have saddened she could have saddened we could have saddened you could have saddened they could have saddened
V-ing perfect
I could have been saddening you could have been saddening she could have been saddening we could have been saddening you could have been saddening they could have been saddening
Negation
Simple form
I couldn't sadden you couldn't sadden she couldn't sadden we couldn't sadden you couldn't sadden they couldn't sadden
V-ing form
I couldn't be saddening you couldn't be saddening she couldn't be saddening we couldn't be saddening you couldn't be saddening they couldn't be saddening
Perfect
I couldn't have saddened you couldn't have saddened she couldn't have saddened we couldn't have saddened you couldn't have saddened they couldn't have saddened
V-ing perfect
I couldn't have been saddening you couldn't have been saddening she couldn't have been saddening we couldn't have been saddening you couldn't have been saddening they couldn't have been saddening
Interrogative form
Simple form
could I sadden? could you sadden? could she sadden? could we sadden? could you sadden? could they sadden?
V-ing form
could I be saddening? could you be saddening? could she be saddening? could we be saddening? could you be saddening? could they be saddening?
Perfect
could I have saddened? could you have saddened? could she have saddened? could we have saddened? could you have saddened? could they have saddened?
V-ing perfect
could I have been saddening? could you have been saddening? could she have been saddening? could we have been saddening? could you have been saddening? could they have been saddening?
Interro-negative form
Simple form
couldn't I sadden? couldn't you sadden? couldn't she sadden? couldn't we sadden? couldn't you sadden? couldn't they sadden?
V-ing form
couldn't I be saddening? couldn't you be saddening? couldn't she be saddening? couldn't we be saddening? couldn't you be saddening? couldn't they be saddening?
Perfect
couldn't I have saddened? couldn't you have saddened? couldn't she have saddened? couldn't we have saddened? couldn't you have saddened? couldn't they have saddened?
V-ing perfect
couldn't I have been saddening? couldn't you have been saddening? couldn't she have been saddening? couldn't we have been saddening? couldn't you have been saddening? couldn't they have been saddening?