I could boom you could boom she could boom we could boom you could boom they could boom
V-ing form
I could be booming you could be booming she could be booming we could be booming you could be booming they could be booming
Perfect
I could have boomed you could have boomed she could have boomed we could have boomed you could have boomed they could have boomed
V-ing perfect
I could have been booming you could have been booming she could have been booming we could have been booming you could have been booming they could have been booming
Negation
Simple form
I could not boom you could not boom she could not boom we could not boom you could not boom they could not boom
V-ing form
I could not be booming you could not be booming she could not be booming we could not be booming you could not be booming they could not be booming
Perfect
I could not have boomed you could not have boomed she could not have boomed we could not have boomed you could not have boomed they could not have boomed
V-ing perfect
I could not have been booming you could not have been booming she could not have been booming we could not have been booming you could not have been booming they could not have been booming
Interrogative form
Simple form
could I boom? could you boom? could she boom? could we boom? could you boom? could they boom?
V-ing form
could I be booming? could you be booming? could she be booming? could we be booming? could you be booming? could they be booming?
Perfect
could I have boomed? could you have boomed? could she have boomed? could we have boomed? could you have boomed? could they have boomed?
V-ing perfect
could I have been booming? could you have been booming? could she have been booming? could we have been booming? could you have been booming? could they have been booming?
Interro-negative form
Simple form
could I not boom? could you not boom? could she not boom? could we not boom? could you not boom? could they not boom?
V-ing form
could I not be booming? could you not be booming? could she not be booming? could we not be booming? could you not be booming? could they not be booming?
Perfect
could I not have boomed? could you not have boomed? could she not have boomed? could we not have boomed? could you not have boomed? could they not have boomed?
V-ing perfect
could I not have been booming? could you not have been booming? could she not have been booming? could we not have been booming? could you not have been booming? could they not have been booming?