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