I can throb you can throb he can throb we can throb you can throb they can throb
V-ing form
I can be throbbing you can be throbbing he can be throbbing we can be throbbing you can be throbbing they can be throbbing
Perfect
I can have throbbed you can have throbbed he can have throbbed we can have throbbed you can have throbbed they can have throbbed
V-ing perfect
I can have been throbbing you can have been throbbing he can have been throbbing we can have been throbbing you can have been throbbing they can have been throbbing
Negation
Simple form
I can't throb you can't throb he can't throb we can't throb you can't throb they can't throb
V-ing form
I can't be throbbing you can't be throbbing he can't be throbbing we can't be throbbing you can't be throbbing they can't be throbbing
Perfect
I can't have throbbed you can't have throbbed he can't have throbbed we can't have throbbed you can't have throbbed they can't have throbbed
V-ing perfect
I can't have been throbbing you can't have been throbbing he can't have been throbbing we can't have been throbbing you can't have been throbbing they can't have been throbbing
Interrogative form
Simple form
can I throb? can you throb? can he throb? can we throb? can you throb? can they throb?
V-ing form
can I be throbbing? can you be throbbing? can he be throbbing? can we be throbbing? can you be throbbing? can they be throbbing?
Perfect
can I have throbbed? can you have throbbed? can he have throbbed? can we have throbbed? can you have throbbed? can they have throbbed?
V-ing perfect
can I have been throbbing? can you have been throbbing? can he have been throbbing? can we have been throbbing? can you have been throbbing? can they have been throbbing?
Interro-negative form
Simple form
can't I throb? can't you throb? can't he throb? can't we throb? can't you throb? can't they throb?
V-ing form
can't I be throbbing? can't you be throbbing? can't he be throbbing? can't we be throbbing? can't you be throbbing? can't they be throbbing?
Perfect
can't I have throbbed? can't you have throbbed? can't he have throbbed? can't we have throbbed? can't you have throbbed? can't they have throbbed?
V-ing perfect
can't I have been throbbing? can't you have been throbbing? can't he have been throbbing? can't we have been throbbing? can't you have been throbbing? can't they have been throbbing?