English verb conjugation
COULD SURF

Regular verb: surf - surfed - surfed

Affirmation

Simple form	V-ing form
I could surf you could surf he could surf we could surf you could surf they could surf	I could be surfing you could be surfing he could be surfing we could be surfing you could be surfing they could be surfing
Perfect	V-ing perfect
I could have surfed you could have surfed he could have surfed we could have surfed you could have surfed they could have surfed	I could have been surfing you could have been surfing he could have been surfing we could have been surfing you could have been surfing they could have been surfing

Negation

Simple form	V-ing form
I couldn't surf you couldn't surf he couldn't surf we couldn't surf you couldn't surf they couldn't surf	I couldn't be surfing you couldn't be surfing he couldn't be surfing we couldn't be surfing you couldn't be surfing they couldn't be surfing
Perfect	V-ing perfect
I couldn't have surfed you couldn't have surfed he couldn't have surfed we couldn't have surfed you couldn't have surfed they couldn't have surfed	I couldn't have been surfing you couldn't have been surfing he couldn't have been surfing we couldn't have been surfing you couldn't have been surfing they couldn't have been surfing

Interrogative form

Simple form	V-ing form
could I surf? could you surf? could he surf? could we surf? could you surf? could they surf?	could I be surfing? could you be surfing? could he be surfing? could we be surfing? could you be surfing? could they be surfing?
Perfect	V-ing perfect
could I have surfed? could you have surfed? could he have surfed? could we have surfed? could you have surfed? could they have surfed?	could I have been surfing? could you have been surfing? could he have been surfing? could we have been surfing? could you have been surfing? could they have been surfing?

Interro-negative form

Simple form	V-ing form
couldn't I surf? couldn't you surf? couldn't he surf? couldn't we surf? couldn't you surf? couldn't they surf?	couldn't I be surfing? couldn't you be surfing? couldn't he be surfing? couldn't we be surfing? couldn't you be surfing? couldn't they be surfing?
Perfect	V-ing perfect
couldn't I have surfed? couldn't you have surfed? couldn't he have surfed? couldn't we have surfed? couldn't you have surfed? couldn't they have surfed?	couldn't I have been surfing? couldn't you have been surfing? couldn't he have been surfing? couldn't we have been surfing? couldn't you have been surfing? couldn't they have been surfing?