I could cross you could cross she could cross we could cross you could cross they could cross
V-ing form
I could be crossing you could be crossing she could be crossing we could be crossing you could be crossing they could be crossing
Perfect
I could have crossed you could have crossed she could have crossed we could have crossed you could have crossed they could have crossed
V-ing perfect
I could have been crossing you could have been crossing she could have been crossing we could have been crossing you could have been crossing they could have been crossing
Negation
Simple form
I couldn't cross you couldn't cross she couldn't cross we couldn't cross you couldn't cross they couldn't cross
V-ing form
I couldn't be crossing you couldn't be crossing she couldn't be crossing we couldn't be crossing you couldn't be crossing they couldn't be crossing
Perfect
I couldn't have crossed you couldn't have crossed she couldn't have crossed we couldn't have crossed you couldn't have crossed they couldn't have crossed
V-ing perfect
I couldn't have been crossing you couldn't have been crossing she couldn't have been crossing we couldn't have been crossing you couldn't have been crossing they couldn't have been crossing
Interrogative form
Simple form
could I cross? could you cross? could she cross? could we cross? could you cross? could they cross?
V-ing form
could I be crossing? could you be crossing? could she be crossing? could we be crossing? could you be crossing? could they be crossing?
Perfect
could I have crossed? could you have crossed? could she have crossed? could we have crossed? could you have crossed? could they have crossed?
V-ing perfect
could I have been crossing? could you have been crossing? could she have been crossing? could we have been crossing? could you have been crossing? could they have been crossing?
Interro-negative form
Simple form
couldn't I cross? couldn't you cross? couldn't she cross? couldn't we cross? couldn't you cross? couldn't they cross?
V-ing form
couldn't I be crossing? couldn't you be crossing? couldn't she be crossing? couldn't we be crossing? couldn't you be crossing? couldn't they be crossing?
Perfect
couldn't I have crossed? couldn't you have crossed? couldn't she have crossed? couldn't we have crossed? couldn't you have crossed? couldn't they have crossed?
V-ing perfect
couldn't I have been crossing? couldn't you have been crossing? couldn't she have been crossing? couldn't we have been crossing? couldn't you have been crossing? couldn't they have been crossing?