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