I could search you could search she could search we could search you could search they could search
V-ing form
I could be searching you could be searching she could be searching we could be searching you could be searching they could be searching
Perfect
I could have searched you could have searched she could have searched we could have searched you could have searched they could have searched
V-ing perfect
I could have been searching you could have been searching she could have been searching we could have been searching you could have been searching they could have been searching
Negation
Simple form
I could not search you could not search she could not search we could not search you could not search they could not search
V-ing form
I could not be searching you could not be searching she could not be searching we could not be searching you could not be searching they could not be searching
Perfect
I could not have searched you could not have searched she could not have searched we could not have searched you could not have searched they could not have searched
V-ing perfect
I could not have been searching you could not have been searching she could not have been searching we could not have been searching you could not have been searching they could not have been searching
Interrogative form
Simple form
could I search? could you search? could she search? could we search? could you search? could they search?
V-ing form
could I be searching? could you be searching? could she be searching? could we be searching? could you be searching? could they be searching?
Perfect
could I have searched? could you have searched? could she have searched? could we have searched? could you have searched? could they have searched?
V-ing perfect
could I have been searching? could you have been searching? could she have been searching? could we have been searching? could you have been searching? could they have been searching?
Interro-negative form
Simple form
could I not search? could you not search? could she not search? could we not search? could you not search? could they not search?
V-ing form
could I not be searching? could you not be searching? could she not be searching? could we not be searching? could you not be searching? could they not be searching?
Perfect
could I not have searched? could you not have searched? could she not have searched? could we not have searched? could you not have searched? could they not have searched?
V-ing perfect
could I not have been searching? could you not have been searching? could she not have been searching? could we not have been searching? could you not have been searching? could they not have been searching?