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