could relapse
Regular verb: relapse - relapsed- relapsed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could relapse
you could relapse
he could relapse
we could relapse
you could relapse
they could relapse 	I could be relapsing
you could be relapsing
he could be relapsing
we could be relapsing
you could be relapsing
they could be relapsing	I could have relapsed
you could have relapsed
he could have relapsed
we could have relapsed
you could have relapsed
they could have relapsed	I could have been relapsing
you could have been relapsing
he could have been relapsing
we could have been relapsing
you could have been relapsing
they could have been relapsing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not relapse
you could not relapse
he could not relapse
we could not relapse
you could not relapse
they could not relapse 	I could not be relapsing
you could not be relapsing
he could not be relapsing
we could not be relapsing
you could not be relapsing
they could not be relapsing	I could not have relapsed
you could not have relapsed
he could not have relapsed
we could not have relapsed
you could not have relapsed
they could not have relapsed	I could not have been relapsing
you could not have been relapsing
he could not have been relapsing
we could not have been relapsing
you could not have been relapsing
they could not have been relapsing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I relapse?
could you relapse?
could he relapse?
could we relapse?
could you relapse?
could they relapse? 	could I be relapsing?
could you be relapsing?
could he be relapsing?
could we be relapsing?
could you be relapsing?
could they be relapsing? 	could I have relapsed?
could you have relapsed?
could he have relapsed?
could we have relapsed?
could you have relapsed?
could they have relapsed? 	could I have been relapsing?
could you have been relapsing?
could he have been relapsing?
could we have been relapsing?
could you have been relapsing?
could they have been relapsing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not relapse?
could you not relapse?
could he not relapse?
could we not relapse?
could you not relapse?
could they not relapse? 	could I not be relapsing?
could you not be relapsing?
could he not be relapsing?
could we not be relapsing?
could you not be relapsing?
could they not be relapsing? 	could I not have relapsed?
could you not have relapsed?
could he not have relapsed?
could we not have relapsed?
could you not have relapsed?
could they not have relapsed? 	could I not have been relapsing?
could you not have been relapsing?
could he not have been relapsing?
could we not have been relapsing?
could you not have been relapsing?
could they not have been relapsing?