I can vacillate you can vacillate he can vacillate we can vacillate you can vacillate they can vacillate
V-ing form
I can be vacillating you can be vacillating he can be vacillating we can be vacillating you can be vacillating they can be vacillating
Perfect
I can have vacillated you can have vacillated he can have vacillated we can have vacillated you can have vacillated they can have vacillated
V-ing perfect
I can have been vacillating you can have been vacillating he can have been vacillating we can have been vacillating you can have been vacillating they can have been vacillating
Negation
Simple form
I can't vacillate you can't vacillate he can't vacillate we can't vacillate you can't vacillate they can't vacillate
V-ing form
I can't be vacillating you can't be vacillating he can't be vacillating we can't be vacillating you can't be vacillating they can't be vacillating
Perfect
I can't have vacillated you can't have vacillated he can't have vacillated we can't have vacillated you can't have vacillated they can't have vacillated
V-ing perfect
I can't have been vacillating you can't have been vacillating he can't have been vacillating we can't have been vacillating you can't have been vacillating they can't have been vacillating
Interrogative form
Simple form
can I vacillate? can you vacillate? can he vacillate? can we vacillate? can you vacillate? can they vacillate?
V-ing form
can I be vacillating? can you be vacillating? can he be vacillating? can we be vacillating? can you be vacillating? can they be vacillating?
Perfect
can I have vacillated? can you have vacillated? can he have vacillated? can we have vacillated? can you have vacillated? can they have vacillated?
V-ing perfect
can I have been vacillating? can you have been vacillating? can he have been vacillating? can we have been vacillating? can you have been vacillating? can they have been vacillating?
Interro-negative form
Simple form
can't I vacillate? can't you vacillate? can't he vacillate? can't we vacillate? can't you vacillate? can't they vacillate?
V-ing form
can't I be vacillating? can't you be vacillating? can't he be vacillating? can't we be vacillating? can't you be vacillating? can't they be vacillating?
Perfect
can't I have vacillated? can't you have vacillated? can't he have vacillated? can't we have vacillated? can't you have vacillated? can't they have vacillated?
V-ing perfect
can't I have been vacillating? can't you have been vacillating? can't he have been vacillating? can't we have been vacillating? can't you have been vacillating? can't they have been vacillating?