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