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