I can fortify you can fortify he can fortify we can fortify you can fortify they can fortify
V-ing form
I can be fortifying you can be fortifying he can be fortifying we can be fortifying you can be fortifying they can be fortifying
Perfect
I can have fortified you can have fortified he can have fortified we can have fortified you can have fortified they can have fortified
V-ing perfect
I can have been fortifying you can have been fortifying he can have been fortifying we can have been fortifying you can have been fortifying they can have been fortifying
Negation
Simple form
I can't fortify you can't fortify he can't fortify we can't fortify you can't fortify they can't fortify
V-ing form
I can't be fortifying you can't be fortifying he can't be fortifying we can't be fortifying you can't be fortifying they can't be fortifying
Perfect
I can't have fortified you can't have fortified he can't have fortified we can't have fortified you can't have fortified they can't have fortified
V-ing perfect
I can't have been fortifying you can't have been fortifying he can't have been fortifying we can't have been fortifying you can't have been fortifying they can't have been fortifying
Interrogative form
Simple form
can I fortify? can you fortify? can he fortify? can we fortify? can you fortify? can they fortify?
V-ing form
can I be fortifying? can you be fortifying? can he be fortifying? can we be fortifying? can you be fortifying? can they be fortifying?
Perfect
can I have fortified? can you have fortified? can he have fortified? can we have fortified? can you have fortified? can they have fortified?
V-ing perfect
can I have been fortifying? can you have been fortifying? can he have been fortifying? can we have been fortifying? can you have been fortifying? can they have been fortifying?
Interro-negative form
Simple form
can't I fortify? can't you fortify? can't he fortify? can't we fortify? can't you fortify? can't they fortify?
V-ing form
can't I be fortifying? can't you be fortifying? can't he be fortifying? can't we be fortifying? can't you be fortifying? can't they be fortifying?
Perfect
can't I have fortified? can't you have fortified? can't he have fortified? can't we have fortified? can't you have fortified? can't they have fortified?
V-ing perfect
can't I have been fortifying? can't you have been fortifying? can't he have been fortifying? can't we have been fortifying? can't you have been fortifying? can't they have been fortifying?