I could stroll you could stroll he could stroll we could stroll you could stroll they could stroll
V-ing form
I could be strolling you could be strolling he could be strolling we could be strolling you could be strolling they could be strolling
Perfect
I could have strolled you could have strolled he could have strolled we could have strolled you could have strolled they could have strolled
V-ing perfect
I could have been strolling you could have been strolling he could have been strolling we could have been strolling you could have been strolling they could have been strolling
Negation
Simple form
I couldn't stroll you couldn't stroll he couldn't stroll we couldn't stroll you couldn't stroll they couldn't stroll
V-ing form
I couldn't be strolling you couldn't be strolling he couldn't be strolling we couldn't be strolling you couldn't be strolling they couldn't be strolling
Perfect
I couldn't have strolled you couldn't have strolled he couldn't have strolled we couldn't have strolled you couldn't have strolled they couldn't have strolled
V-ing perfect
I couldn't have been strolling you couldn't have been strolling he couldn't have been strolling we couldn't have been strolling you couldn't have been strolling they couldn't have been strolling
Interrogative form
Simple form
could I stroll? could you stroll? could he stroll? could we stroll? could you stroll? could they stroll?
V-ing form
could I be strolling? could you be strolling? could he be strolling? could we be strolling? could you be strolling? could they be strolling?
Perfect
could I have strolled? could you have strolled? could he have strolled? could we have strolled? could you have strolled? could they have strolled?
V-ing perfect
could I have been strolling? could you have been strolling? could he have been strolling? could we have been strolling? could you have been strolling? could they have been strolling?
Interro-negative form
Simple form
couldn't I stroll? couldn't you stroll? couldn't he stroll? couldn't we stroll? couldn't you stroll? couldn't they stroll?
V-ing form
couldn't I be strolling? couldn't you be strolling? couldn't he be strolling? couldn't we be strolling? couldn't you be strolling? couldn't they be strolling?
Perfect
couldn't I have strolled? couldn't you have strolled? couldn't he have strolled? couldn't we have strolled? couldn't you have strolled? couldn't they have strolled?
V-ing perfect
couldn't I have been strolling? couldn't you have been strolling? couldn't he have been strolling? couldn't we have been strolling? couldn't you have been strolling? couldn't they have been strolling?