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