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