could lapse
Regular verb: lapse - lapsed- lapsed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could lapse
you could lapse
he could lapse
we could lapse
you could lapse
they could lapse 	I could be lapsing
you could be lapsing
he could be lapsing
we could be lapsing
you could be lapsing
they could be lapsing	I could have lapsed
you could have lapsed
he could have lapsed
we could have lapsed
you could have lapsed
they could have lapsed	I could have been lapsing
you could have been lapsing
he could have been lapsing
we could have been lapsing
you could have been lapsing
they could have been lapsing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't lapse
you couldn't lapse
he couldn't lapse
we couldn't lapse
you couldn't lapse
they couldn't lapse 	I couldn't be lapsing
you couldn't be lapsing
he couldn't be lapsing
we couldn't be lapsing
you couldn't be lapsing
they couldn't be lapsing	I couldn't have lapsed
you couldn't have lapsed
he couldn't have lapsed
we couldn't have lapsed
you couldn't have lapsed
they couldn't have lapsed	I couldn't have been lapsing
you couldn't have been lapsing
he couldn't have been lapsing
we couldn't have been lapsing
you couldn't have been lapsing
they couldn't have been lapsing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I lapse?
could you lapse?
could he lapse?
could we lapse?
could you lapse?
could they lapse? 	could I be lapsing?
could you be lapsing?
could he be lapsing?
could we be lapsing?
could you be lapsing?
could they be lapsing? 	could I have lapsed?
could you have lapsed?
could he have lapsed?
could we have lapsed?
could you have lapsed?
could they have lapsed? 	could I have been lapsing?
could you have been lapsing?
could he have been lapsing?
could we have been lapsing?
could you have been lapsing?
could they have been lapsing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I lapse?
couldn't you lapse?
couldn't he lapse?
couldn't we lapse?
couldn't you lapse?
couldn't they lapse? 	couldn't I be lapsing?
couldn't you be lapsing?
couldn't he be lapsing?
couldn't we be lapsing?
couldn't you be lapsing?
couldn't they be lapsing? 	couldn't I have lapsed?
couldn't you have lapsed?
couldn't he have lapsed?
couldn't we have lapsed?
couldn't you have lapsed?
couldn't they have lapsed? 	couldn't I have been lapsing?
couldn't you have been lapsing?
couldn't he have been lapsing?
couldn't we have been lapsing?
couldn't you have been lapsing?
couldn't they have been lapsing?