I can worry you can worry he can worry we can worry you can worry they can worry
V-ing form
I can be worrying you can be worrying he can be worrying we can be worrying you can be worrying they can be worrying
Perfect
I can have worried you can have worried he can have worried we can have worried you can have worried they can have worried
V-ing perfect
I can have been worrying you can have been worrying he can have been worrying we can have been worrying you can have been worrying they can have been worrying
Negation
Simple form
I cannot worry you cannot worry he cannot worry we cannot worry you cannot worry they cannot worry
V-ing form
I cannot be worrying you cannot be worrying he cannot be worrying we cannot be worrying you cannot be worrying they cannot be worrying
Perfect
I cannot have worried you cannot have worried he cannot have worried we cannot have worried you cannot have worried they cannot have worried
V-ing perfect
I cannot have been worrying you cannot have been worrying he cannot have been worrying we cannot have been worrying you cannot have been worrying they cannot have been worrying
Interrogative form
Simple form
can I worry? can you worry? can he worry? can we worry? can you worry? can they worry?
V-ing form
can I be worrying? can you be worrying? can he be worrying? can we be worrying? can you be worrying? can they be worrying?
Perfect
can I have worried? can you have worried? can he have worried? can we have worried? can you have worried? can they have worried?
V-ing perfect
can I have been worrying? can you have been worrying? can he have been worrying? can we have been worrying? can you have been worrying? can they have been worrying?
Interro-negative form
Simple form
can I not worry? can you not worry? can he not worry? can we not worry? can you not worry? can they not worry?
V-ing form
can I not be worrying? can you not be worrying? can he not be worrying? can we not be worrying? can you not be worrying? can they not be worrying?
Perfect
can I not have worried? can you not have worried? can he not have worried? can we not have worried? can you not have worried? can they not have worried?
V-ing perfect
can I not have been worrying? can you not have been worrying? can he not have been worrying? can we not have been worrying? can you not have been worrying? can they not have been worrying?