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