can knife
Regular verb: knife - knifed- knifed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can knife
you can knife
he can knife
we can knife
you can knife
they can knife 	I can be knifing
you can be knifing
he can be knifing
we can be knifing
you can be knifing
they can be knifing	I can have knifed
you can have knifed
he can have knifed
we can have knifed
you can have knifed
they can have knifed	I can have been knifing
you can have been knifing
he can have been knifing
we can have been knifing
you can have been knifing
they can have been knifing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot knife
you cannot knife
he cannot knife
we cannot knife
you cannot knife
they cannot knife 	I cannot be knifing
you cannot be knifing
he cannot be knifing
we cannot be knifing
you cannot be knifing
they cannot be knifing	I cannot have knifed
you cannot have knifed
he cannot have knifed
we cannot have knifed
you cannot have knifed
they cannot have knifed	I cannot have been knifing
you cannot have been knifing
he cannot have been knifing
we cannot have been knifing
you cannot have been knifing
they cannot have been knifing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I knife?
can you knife?
can he knife?
can we knife?
can you knife?
can they knife? 	can I be knifing?
can you be knifing?
can he be knifing?
can we be knifing?
can you be knifing?
can they be knifing? 	can I have knifed?
can you have knifed?
can he have knifed?
can we have knifed?
can you have knifed?
can they have knifed? 	can I have been knifing?
can you have been knifing?
can he have been knifing?
can we have been knifing?
can you have been knifing?
can they have been knifing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not knife?
can you not knife?
can he not knife?
can we not knife?
can you not knife?
can they not knife? 	can I not be knifing?
can you not be knifing?
can he not be knifing?
can we not be knifing?
can you not be knifing?
can they not be knifing? 	can I not have knifed?
can you not have knifed?
can he not have knifed?
can we not have knifed?
can you not have knifed?
can they not have knifed? 	can I not have been knifing?
can you not have been knifing?
can he not have been knifing?
can we not have been knifing?
can you not have been knifing?
can they not have been knifing?