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