I can protest you can protest he can protest we can protest you can protest they can protest
V-ing form
I can be protesting you can be protesting he can be protesting we can be protesting you can be protesting they can be protesting
Perfect
I can have protested you can have protested he can have protested we can have protested you can have protested they can have protested
V-ing perfect
I can have been protesting you can have been protesting he can have been protesting we can have been protesting you can have been protesting they can have been protesting
Negation
Simple form
I can't protest you can't protest he can't protest we can't protest you can't protest they can't protest
V-ing form
I can't be protesting you can't be protesting he can't be protesting we can't be protesting you can't be protesting they can't be protesting
Perfect
I can't have protested you can't have protested he can't have protested we can't have protested you can't have protested they can't have protested
V-ing perfect
I can't have been protesting you can't have been protesting he can't have been protesting we can't have been protesting you can't have been protesting they can't have been protesting
Interrogative form
Simple form
can I protest? can you protest? can he protest? can we protest? can you protest? can they protest?
V-ing form
can I be protesting? can you be protesting? can he be protesting? can we be protesting? can you be protesting? can they be protesting?
Perfect
can I have protested? can you have protested? can he have protested? can we have protested? can you have protested? can they have protested?
V-ing perfect
can I have been protesting? can you have been protesting? can he have been protesting? can we have been protesting? can you have been protesting? can they have been protesting?
Interro-negative form
Simple form
can't I protest? can't you protest? can't he protest? can't we protest? can't you protest? can't they protest?
V-ing form
can't I be protesting? can't you be protesting? can't he be protesting? can't we be protesting? can't you be protesting? can't they be protesting?
Perfect
can't I have protested? can't you have protested? can't he have protested? can't we have protested? can't you have protested? can't they have protested?
V-ing perfect
can't I have been protesting? can't you have been protesting? can't he have been protesting? can't we have been protesting? can't you have been protesting? can't they have been protesting?