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