can collapse
Regular verb: collapse - collapsed- collapsed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can collapse
you can collapse
he can collapse
we can collapse
you can collapse
they can collapse 	I can be collapsing
you can be collapsing
he can be collapsing
we can be collapsing
you can be collapsing
they can be collapsing	I can have collapsed
you can have collapsed
he can have collapsed
we can have collapsed
you can have collapsed
they can have collapsed	I can have been collapsing
you can have been collapsing
he can have been collapsing
we can have been collapsing
you can have been collapsing
they can have been collapsing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot collapse
you cannot collapse
he cannot collapse
we cannot collapse
you cannot collapse
they cannot collapse 	I cannot be collapsing
you cannot be collapsing
he cannot be collapsing
we cannot be collapsing
you cannot be collapsing
they cannot be collapsing	I cannot have collapsed
you cannot have collapsed
he cannot have collapsed
we cannot have collapsed
you cannot have collapsed
they cannot have collapsed	I cannot have been collapsing
you cannot have been collapsing
he cannot have been collapsing
we cannot have been collapsing
you cannot have been collapsing
they cannot have been collapsing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I collapse?
can you collapse?
can he collapse?
can we collapse?
can you collapse?
can they collapse? 	can I be collapsing?
can you be collapsing?
can he be collapsing?
can we be collapsing?
can you be collapsing?
can they be collapsing? 	can I have collapsed?
can you have collapsed?
can he have collapsed?
can we have collapsed?
can you have collapsed?
can they have collapsed? 	can I have been collapsing?
can you have been collapsing?
can he have been collapsing?
can we have been collapsing?
can you have been collapsing?
can they have been collapsing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not collapse?
can you not collapse?
can he not collapse?
can we not collapse?
can you not collapse?
can they not collapse? 	can I not be collapsing?
can you not be collapsing?
can he not be collapsing?
can we not be collapsing?
can you not be collapsing?
can they not be collapsing? 	can I not have collapsed?
can you not have collapsed?
can he not have collapsed?
can we not have collapsed?
can you not have collapsed?
can they not have collapsed? 	can I not have been collapsing?
can you not have been collapsing?
can he not have been collapsing?
can we not have been collapsing?
can you not have been collapsing?
can they not have been collapsing?