I could pitterpatter you could pitterpatter he could pitterpatter we could pitterpatter you could pitterpatter they could pitterpatter
V-ing form
I could be pitterpattering you could be pitterpattering he could be pitterpattering we could be pitterpattering you could be pitterpattering they could be pitterpattering
Perfect
I could have pitterpattered you could have pitterpattered he could have pitterpattered we could have pitterpattered you could have pitterpattered they could have pitterpattered
V-ing perfect
I could have been pitterpattering you could have been pitterpattering he could have been pitterpattering we could have been pitterpattering you could have been pitterpattering they could have been pitterpattering
Negation
Simple form
I could not pitterpatter you could not pitterpatter he could not pitterpatter we could not pitterpatter you could not pitterpatter they could not pitterpatter
V-ing form
I could not be pitterpattering you could not be pitterpattering he could not be pitterpattering we could not be pitterpattering you could not be pitterpattering they could not be pitterpattering
Perfect
I could not have pitterpattered you could not have pitterpattered he could not have pitterpattered we could not have pitterpattered you could not have pitterpattered they could not have pitterpattered
V-ing perfect
I could not have been pitterpattering you could not have been pitterpattering he could not have been pitterpattering we could not have been pitterpattering you could not have been pitterpattering they could not have been pitterpattering
Interrogative form
Simple form
could I pitterpatter? could you pitterpatter? could he pitterpatter? could we pitterpatter? could you pitterpatter? could they pitterpatter?
V-ing form
could I be pitterpattering? could you be pitterpattering? could he be pitterpattering? could we be pitterpattering? could you be pitterpattering? could they be pitterpattering?
Perfect
could I have pitterpattered? could you have pitterpattered? could he have pitterpattered? could we have pitterpattered? could you have pitterpattered? could they have pitterpattered?
V-ing perfect
could I have been pitterpattering? could you have been pitterpattering? could he have been pitterpattering? could we have been pitterpattering? could you have been pitterpattering? could they have been pitterpattering?
Interro-negative form
Simple form
could I not pitterpatter? could you not pitterpatter? could he not pitterpatter? could we not pitterpatter? could you not pitterpatter? could they not pitterpatter?
V-ing form
could I not be pitterpattering? could you not be pitterpattering? could he not be pitterpattering? could we not be pitterpattering? could you not be pitterpattering? could they not be pitterpattering?
Perfect
could I not have pitterpattered? could you not have pitterpattered? could he not have pitterpattered? could we not have pitterpattered? could you not have pitterpattered? could they not have pitterpattered?
V-ing perfect
could I not have been pitterpattering? could you not have been pitterpattering? could he not have been pitterpattering? could we not have been pitterpattering? could you not have been pitterpattering? could they not have been pitterpattering?