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