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