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