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