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 couldn't kayak you couldn't kayak he couldn't kayak we couldn't kayak you couldn't kayak they couldn't kayak
V-ing form
I couldn't be kayaking you couldn't be kayaking he couldn't be kayaking we couldn't be kayaking you couldn't be kayaking they couldn't be kayaking
Perfect
I couldn't have kayaked you couldn't have kayaked he couldn't have kayaked we couldn't have kayaked you couldn't have kayaked they couldn't have kayaked
V-ing perfect
I couldn't have been kayaking you couldn't have been kayaking he couldn't have been kayaking we couldn't have been kayaking you couldn't have been kayaking they couldn't 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
couldn't I kayak? couldn't you kayak? couldn't he kayak? couldn't we kayak? couldn't you kayak? couldn't they kayak?
V-ing form
couldn't I be kayaking? couldn't you be kayaking? couldn't he be kayaking? couldn't we be kayaking? couldn't you be kayaking? couldn't they be kayaking?
Perfect
couldn't I have kayaked? couldn't you have kayaked? couldn't he have kayaked? couldn't we have kayaked? couldn't you have kayaked? couldn't they have kayaked?
V-ing perfect
couldn't I have been kayaking? couldn't you have been kayaking? couldn't he have been kayaking? couldn't we have been kayaking? couldn't you have been kayaking? couldn't they have been kayaking?