can crack
Regular verb: crack - cracked- cracked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can crack
you can crack
he can crack
we can crack
you can crack
they can crack 	I can be cracking
you can be cracking
he can be cracking
we can be cracking
you can be cracking
they can be cracking	I can have cracked
you can have cracked
he can have cracked
we can have cracked
you can have cracked
they can have cracked	I can have been cracking
you can have been cracking
he can have been cracking
we can have been cracking
you can have been cracking
they can have been cracking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't crack
you can't crack
he can't crack
we can't crack
you can't crack
they can't crack 	I can't be cracking
you can't be cracking
he can't be cracking
we can't be cracking
you can't be cracking
they can't be cracking	I can't have cracked
you can't have cracked
he can't have cracked
we can't have cracked
you can't have cracked
they can't have cracked	I can't have been cracking
you can't have been cracking
he can't have been cracking
we can't have been cracking
you can't have been cracking
they can't have been cracking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I crack?
can you crack?
can he crack?
can we crack?
can you crack?
can they crack? 	can I be cracking?
can you be cracking?
can he be cracking?
can we be cracking?
can you be cracking?
can they be cracking? 	can I have cracked?
can you have cracked?
can he have cracked?
can we have cracked?
can you have cracked?
can they have cracked? 	can I have been cracking?
can you have been cracking?
can he have been cracking?
can we have been cracking?
can you have been cracking?
can they have been cracking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I crack?
can't you crack?
can't he crack?
can't we crack?
can't you crack?
can't they crack? 	can't I be cracking?
can't you be cracking?
can't he be cracking?
can't we be cracking?
can't you be cracking?
can't they be cracking? 	can't I have cracked?
can't you have cracked?
can't he have cracked?
can't we have cracked?
can't you have cracked?
can't they have cracked? 	can't I have been cracking?
can't you have been cracking?
can't he have been cracking?
can't we have been cracking?
can't you have been cracking?
can't they have been cracking?