I could kayak you could kayak he could kayak we could kayak you could kayak they could kayak
V-ing form
I could be kayaking you could be kayaking he could be kayaking we could be kayaking you could be kayaking they could be kayaking
Perfect
I could have kayaked you could have kayaked he could have kayaked we could have kayaked you could have kayaked they could have kayaked
V-ing perfect
I could have been kayaking you could have been kayaking he could have been kayaking we could have been kayaking you could have been kayaking they could have been kayaking
Negation
Simple form
I could not kayak you could not kayak he could not kayak we could not kayak you could not kayak they could not kayak
V-ing form
I could not be kayaking you could not be kayaking he could not be kayaking we could not be kayaking you could not be kayaking they could not be kayaking
Perfect
I could not have kayaked you could not have kayaked he could not have kayaked we could not have kayaked you could not have kayaked they could not have kayaked
V-ing perfect
I could not have been kayaking you could not have been kayaking he could not have been kayaking we could not have been kayaking you could not have been kayaking they could not have been kayaking
Interrogative form
Simple form
could I kayak? could you kayak? could he kayak? could we kayak? could you kayak? could they kayak?
V-ing form
could I be kayaking? could you be kayaking? could he be kayaking? could we be kayaking? could you be kayaking? could they be kayaking?
Perfect
could I have kayaked? could you have kayaked? could he have kayaked? could we have kayaked? could you have kayaked? could they have kayaked?
V-ing perfect
could I have been kayaking? could you have been kayaking? could he have been kayaking? could we have been kayaking? could you have been kayaking? could they have been kayaking?
Interro-negative form
Simple form
could I not kayak? could you not kayak? could he not kayak? could we not kayak? could you not kayak? could they not kayak?
V-ing form
could I not be kayaking? could you not be kayaking? could he not be kayaking? could we not be kayaking? could you not be kayaking? could they not be kayaking?
Perfect
could I not have kayaked? could you not have kayaked? could he not have kayaked? could we not have kayaked? could you not have kayaked? could they not have kayaked?
V-ing perfect
could I not have been kayaking? could you not have been kayaking? could he not have been kayaking? could we not have been kayaking? could you not have been kayaking? could they not have been kayaking?