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