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