I could bite you could bite she could bite we could bite you could bite they could bite
V-ing form
I could be biting you could be biting she could be biting we could be biting you could be biting they could be biting
Perfect
I could have bitten you could have bitten she could have bitten we could have bitten you could have bitten they could have bitten
V-ing perfect
I could have been biting you could have been biting she could have been biting we could have been biting you could have been biting they could have been biting
Negation
Simple form
I couldn't bite you couldn't bite she couldn't bite we couldn't bite you couldn't bite they couldn't bite
V-ing form
I couldn't be biting you couldn't be biting she couldn't be biting we couldn't be biting you couldn't be biting they couldn't be biting
Perfect
I couldn't have bitten you couldn't have bitten she couldn't have bitten we couldn't have bitten you couldn't have bitten they couldn't have bitten
V-ing perfect
I couldn't have been biting you couldn't have been biting she couldn't have been biting we couldn't have been biting you couldn't have been biting they couldn't have been biting
Interrogative form
Simple form
could I bite? could you bite? could she bite? could we bite? could you bite? could they bite?
V-ing form
could I be biting? could you be biting? could she be biting? could we be biting? could you be biting? could they be biting?
Perfect
could I have bitten? could you have bitten? could she have bitten? could we have bitten? could you have bitten? could they have bitten?
V-ing perfect
could I have been biting? could you have been biting? could she have been biting? could we have been biting? could you have been biting? could they have been biting?
Interro-negative form
Simple form
couldn't I bite? couldn't you bite? couldn't she bite? couldn't we bite? couldn't you bite? couldn't they bite?
V-ing form
couldn't I be biting? couldn't you be biting? couldn't she be biting? couldn't we be biting? couldn't you be biting? couldn't they be biting?
Perfect
couldn't I have bitten? couldn't you have bitten? couldn't she have bitten? couldn't we have bitten? couldn't you have bitten? couldn't they have bitten?
V-ing perfect
couldn't I have been biting? couldn't you have been biting? couldn't she have been biting? couldn't we have been biting? couldn't you have been biting? couldn't they have been biting?