I can fax you can fax he can fax we can fax you can fax they can fax
V-ing form
I can be faxing you can be faxing he can be faxing we can be faxing you can be faxing they can be faxing
Perfect
I can have faxed you can have faxed he can have faxed we can have faxed you can have faxed they can have faxed
V-ing perfect
I can have been faxing you can have been faxing he can have been faxing we can have been faxing you can have been faxing they can have been faxing
Negation
Simple form
I can't fax you can't fax he can't fax we can't fax you can't fax they can't fax
V-ing form
I can't be faxing you can't be faxing he can't be faxing we can't be faxing you can't be faxing they can't be faxing
Perfect
I can't have faxed you can't have faxed he can't have faxed we can't have faxed you can't have faxed they can't have faxed
V-ing perfect
I can't have been faxing you can't have been faxing he can't have been faxing we can't have been faxing you can't have been faxing they can't have been faxing
Interrogative form
Simple form
can I fax? can you fax? can he fax? can we fax? can you fax? can they fax?
V-ing form
can I be faxing? can you be faxing? can he be faxing? can we be faxing? can you be faxing? can they be faxing?
Perfect
can I have faxed? can you have faxed? can he have faxed? can we have faxed? can you have faxed? can they have faxed?
V-ing perfect
can I have been faxing? can you have been faxing? can he have been faxing? can we have been faxing? can you have been faxing? can they have been faxing?
Interro-negative form
Simple form
can't I fax? can't you fax? can't he fax? can't we fax? can't you fax? can't they fax?
V-ing form
can't I be faxing? can't you be faxing? can't he be faxing? can't we be faxing? can't you be faxing? can't they be faxing?
Perfect
can't I have faxed? can't you have faxed? can't he have faxed? can't we have faxed? can't you have faxed? can't they have faxed?
V-ing perfect
can't I have been faxing? can't you have been faxing? can't he have been faxing? can't we have been faxing? can't you have been faxing? can't they have been faxing?