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