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