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