I could pitterpatter you could pitterpatter she could pitterpatter we could pitterpatter you could pitterpatter they could pitterpatter
V-ing form
I could be pitterpattering you could be pitterpattering she could be pitterpattering we could be pitterpattering you could be pitterpattering they could be pitterpattering
Perfect
I could have pitterpattered you could have pitterpattered she 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 she could have been pitterpattering we could have been pitterpattering you could have been pitterpattering they could have been pitterpattering
Negation
Simple form
I couldn't pitterpatter you couldn't pitterpatter she couldn't pitterpatter we couldn't pitterpatter you couldn't pitterpatter they couldn't pitterpatter
V-ing form
I couldn't be pitterpattering you couldn't be pitterpattering she couldn't be pitterpattering we couldn't be pitterpattering you couldn't be pitterpattering they couldn't be pitterpattering
Perfect
I couldn't have pitterpattered you couldn't have pitterpattered she couldn't have pitterpattered we couldn't have pitterpattered you couldn't have pitterpattered they couldn't have pitterpattered
V-ing perfect
I couldn't have been pitterpattering you couldn't have been pitterpattering she couldn't have been pitterpattering we couldn't have been pitterpattering you couldn't have been pitterpattering they couldn't have been pitterpattering
Interrogative form
Simple form
could I pitterpatter? could you pitterpatter? could she pitterpatter? could we pitterpatter? could you pitterpatter? could they pitterpatter?
V-ing form
could I be pitterpattering? could you be pitterpattering? could she be pitterpattering? could we be pitterpattering? could you be pitterpattering? could they be pitterpattering?
Perfect
could I have pitterpattered? could you have pitterpattered? could she 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 she have been pitterpattering? could we have been pitterpattering? could you have been pitterpattering? could they have been pitterpattering?
Interro-negative form
Simple form
couldn't I pitterpatter? couldn't you pitterpatter? couldn't she pitterpatter? couldn't we pitterpatter? couldn't you pitterpatter? couldn't they pitterpatter?
V-ing form
couldn't I be pitterpattering? couldn't you be pitterpattering? couldn't she be pitterpattering? couldn't we be pitterpattering? couldn't you be pitterpattering? couldn't they be pitterpattering?
Perfect
couldn't I have pitterpattered? couldn't you have pitterpattered? couldn't she have pitterpattered? couldn't we have pitterpattered? couldn't you have pitterpattered? couldn't they have pitterpattered?
V-ing perfect
couldn't I have been pitterpattering? couldn't you have been pitterpattering? couldn't she have been pitterpattering? couldn't we have been pitterpattering? couldn't you have been pitterpattering? couldn't they have been pitterpattering?