I could examine you could examine she could examine we could examine you could examine they could examine
V-ing form
I could be examining you could be examining she could be examining we could be examining you could be examining they could be examining
Perfect
I could have examined you could have examined she could have examined we could have examined you could have examined they could have examined
V-ing perfect
I could have been examining you could have been examining she could have been examining we could have been examining you could have been examining they could have been examining
Negation
Simple form
I could not examine you could not examine she could not examine we could not examine you could not examine they could not examine
V-ing form
I could not be examining you could not be examining she could not be examining we could not be examining you could not be examining they could not be examining
Perfect
I could not have examined you could not have examined she could not have examined we could not have examined you could not have examined they could not have examined
V-ing perfect
I could not have been examining you could not have been examining she could not have been examining we could not have been examining you could not have been examining they could not have been examining
Interrogative form
Simple form
could I examine? could you examine? could she examine? could we examine? could you examine? could they examine?
V-ing form
could I be examining? could you be examining? could she be examining? could we be examining? could you be examining? could they be examining?
Perfect
could I have examined? could you have examined? could she have examined? could we have examined? could you have examined? could they have examined?
V-ing perfect
could I have been examining? could you have been examining? could she have been examining? could we have been examining? could you have been examining? could they have been examining?
Interro-negative form
Simple form
could I not examine? could you not examine? could she not examine? could we not examine? could you not examine? could they not examine?
V-ing form
could I not be examining? could you not be examining? could she not be examining? could we not be examining? could you not be examining? could they not be examining?
Perfect
could I not have examined? could you not have examined? could she not have examined? could we not have examined? could you not have examined? could they not have examined?
V-ing perfect
could I not have been examining? could you not have been examining? could she not have been examining? could we not have been examining? could you not have been examining? could they not have been examining?