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