I can intervene you can intervene she can intervene we can intervene you can intervene they can intervene
V-ing form
I can be intervening you can be intervening she can be intervening we can be intervening you can be intervening they can be intervening
Perfect
I can have intervened you can have intervened she can have intervened we can have intervened you can have intervened they can have intervened
V-ing perfect
I can have been intervening you can have been intervening she can have been intervening we can have been intervening you can have been intervening they can have been intervening
Negation
Simple form
I cannot intervene you cannot intervene she cannot intervene we cannot intervene you cannot intervene they cannot intervene
V-ing form
I cannot be intervening you cannot be intervening she cannot be intervening we cannot be intervening you cannot be intervening they cannot be intervening
Perfect
I cannot have intervened you cannot have intervened she cannot have intervened we cannot have intervened you cannot have intervened they cannot have intervened
V-ing perfect
I cannot have been intervening you cannot have been intervening she cannot have been intervening we cannot have been intervening you cannot have been intervening they cannot have been intervening
Interrogative form
Simple form
can I intervene? can you intervene? can she intervene? can we intervene? can you intervene? can they intervene?
V-ing form
can I be intervening? can you be intervening? can she be intervening? can we be intervening? can you be intervening? can they be intervening?
Perfect
can I have intervened? can you have intervened? can she have intervened? can we have intervened? can you have intervened? can they have intervened?
V-ing perfect
can I have been intervening? can you have been intervening? can she have been intervening? can we have been intervening? can you have been intervening? can they have been intervening?
Interro-negative form
Simple form
can I not intervene? can you not intervene? can she not intervene? can we not intervene? can you not intervene? can they not intervene?
V-ing form
can I not be intervening? can you not be intervening? can she not be intervening? can we not be intervening? can you not be intervening? can they not be intervening?
Perfect
can I not have intervened? can you not have intervened? can she not have intervened? can we not have intervened? can you not have intervened? can they not have intervened?
V-ing perfect
can I not have been intervening? can you not have been intervening? can she not have been intervening? can we not have been intervening? can you not have been intervening? can they not have been intervening?