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