I can threaten you can threaten he can threaten we can threaten you can threaten they can threaten
V-ing form
I can be threatening you can be threatening he can be threatening we can be threatening you can be threatening they can be threatening
Perfect
I can have threatened you can have threatened he can have threatened we can have threatened you can have threatened they can have threatened
V-ing perfect
I can have been threatening you can have been threatening he can have been threatening we can have been threatening you can have been threatening they can have been threatening
Negation
Simple form
I can't threaten you can't threaten he can't threaten we can't threaten you can't threaten they can't threaten
V-ing form
I can't be threatening you can't be threatening he can't be threatening we can't be threatening you can't be threatening they can't be threatening
Perfect
I can't have threatened you can't have threatened he can't have threatened we can't have threatened you can't have threatened they can't have threatened
V-ing perfect
I can't have been threatening you can't have been threatening he can't have been threatening we can't have been threatening you can't have been threatening they can't have been threatening
Interrogative form
Simple form
can I threaten? can you threaten? can he threaten? can we threaten? can you threaten? can they threaten?
V-ing form
can I be threatening? can you be threatening? can he be threatening? can we be threatening? can you be threatening? can they be threatening?
Perfect
can I have threatened? can you have threatened? can he have threatened? can we have threatened? can you have threatened? can they have threatened?
V-ing perfect
can I have been threatening? can you have been threatening? can he have been threatening? can we have been threatening? can you have been threatening? can they have been threatening?
Interro-negative form
Simple form
can't I threaten? can't you threaten? can't he threaten? can't we threaten? can't you threaten? can't they threaten?
V-ing form
can't I be threatening? can't you be threatening? can't he be threatening? can't we be threatening? can't you be threatening? can't they be threatening?
Perfect
can't I have threatened? can't you have threatened? can't he have threatened? can't we have threatened? can't you have threatened? can't they have threatened?
V-ing perfect
can't I have been threatening? can't you have been threatening? can't he have been threatening? can't we have been threatening? can't you have been threatening? can't they have been threatening?