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