can combine
Regular verb: combine - combined- combined

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can combine
you can combine
he can combine
we can combine
you can combine
they can combine 	I can be combining
you can be combining
he can be combining
we can be combining
you can be combining
they can be combining	I can have combined
you can have combined
he can have combined
we can have combined
you can have combined
they can have combined	I can have been combining
you can have been combining
he can have been combining
we can have been combining
you can have been combining
they can have been combining	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot combine
you cannot combine
he cannot combine
we cannot combine
you cannot combine
they cannot combine 	I cannot be combining
you cannot be combining
he cannot be combining
we cannot be combining
you cannot be combining
they cannot be combining	I cannot have combined
you cannot have combined
he cannot have combined
we cannot have combined
you cannot have combined
they cannot have combined	I cannot have been combining
you cannot have been combining
he cannot have been combining
we cannot have been combining
you cannot have been combining
they cannot have been combining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I combine?
can you combine?
can he combine?
can we combine?
can you combine?
can they combine? 	can I be combining?
can you be combining?
can he be combining?
can we be combining?
can you be combining?
can they be combining? 	can I have combined?
can you have combined?
can he have combined?
can we have combined?
can you have combined?
can they have combined? 	can I have been combining?
can you have been combining?
can he have been combining?
can we have been combining?
can you have been combining?
can they have been combining? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not combine?
can you not combine?
can he not combine?
can we not combine?
can you not combine?
can they not combine? 	can I not be combining?
can you not be combining?
can he not be combining?
can we not be combining?
can you not be combining?
can they not be combining? 	can I not have combined?
can you not have combined?
can he not have combined?
can we not have combined?
can you not have combined?
can they not have combined? 	can I not have been combining?
can you not have been combining?
can he not have been combining?
can we not have been combining?
can you not have been combining?
can they not have been combining?