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