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