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