I can sob you can sob she can sob we can sob you can sob they can sob
V-ing form
I can be sobbing you can be sobbing she can be sobbing we can be sobbing you can be sobbing they can be sobbing
Perfect
I can have sobbed you can have sobbed she can have sobbed we can have sobbed you can have sobbed they can have sobbed
V-ing perfect
I can have been sobbing you can have been sobbing she can have been sobbing we can have been sobbing you can have been sobbing they can have been sobbing
Negation
Simple form
I can't sob you can't sob she can't sob we can't sob you can't sob they can't sob
V-ing form
I can't be sobbing you can't be sobbing she can't be sobbing we can't be sobbing you can't be sobbing they can't be sobbing
Perfect
I can't have sobbed you can't have sobbed she can't have sobbed we can't have sobbed you can't have sobbed they can't have sobbed
V-ing perfect
I can't have been sobbing you can't have been sobbing she can't have been sobbing we can't have been sobbing you can't have been sobbing they can't have been sobbing
Interrogative form
Simple form
can I sob? can you sob? can she sob? can we sob? can you sob? can they sob?
V-ing form
can I be sobbing? can you be sobbing? can she be sobbing? can we be sobbing? can you be sobbing? can they be sobbing?
Perfect
can I have sobbed? can you have sobbed? can she have sobbed? can we have sobbed? can you have sobbed? can they have sobbed?
V-ing perfect
can I have been sobbing? can you have been sobbing? can she have been sobbing? can we have been sobbing? can you have been sobbing? can they have been sobbing?
Interro-negative form
Simple form
can't I sob? can't you sob? can't she sob? can't we sob? can't you sob? can't they sob?
V-ing form
can't I be sobbing? can't you be sobbing? can't she be sobbing? can't we be sobbing? can't you be sobbing? can't they be sobbing?
Perfect
can't I have sobbed? can't you have sobbed? can't she have sobbed? can't we have sobbed? can't you have sobbed? can't they have sobbed?
V-ing perfect
can't I have been sobbing? can't you have been sobbing? can't she have been sobbing? can't we have been sobbing? can't you have been sobbing? can't they have been sobbing?