I could bestir you could bestir she could bestir we could bestir you could bestir they could bestir
V-ing form
I could be bestirring you could be bestirring she could be bestirring we could be bestirring you could be bestirring they could be bestirring
Perfect
I could have bestirred you could have bestirred she 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 she 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 she 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 she 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 she 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 she 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 she bestir? could we bestir? could you bestir? could they bestir?
V-ing form
could I be bestirring? could you be bestirring? could she be bestirring? could we be bestirring? could you be bestirring? could they be bestirring?
Perfect
could I have bestirred? could you have bestirred? could she 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 she 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 she 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 she 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 she 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 she have been bestirring? couldn't we have been bestirring? couldn't you have been bestirring? couldn't they have been bestirring?