I can suck you can suck he can suck we can suck you can suck they can suck
V-ing form
I can be sucking you can be sucking he can be sucking we can be sucking you can be sucking they can be sucking
Perfect
I can have sucked you can have sucked he can have sucked we can have sucked you can have sucked they can have sucked
V-ing perfect
I can have been sucking you can have been sucking he can have been sucking we can have been sucking you can have been sucking they can have been sucking
Negation
Simple form
I can't suck you can't suck he can't suck we can't suck you can't suck they can't suck
V-ing form
I can't be sucking you can't be sucking he can't be sucking we can't be sucking you can't be sucking they can't be sucking
Perfect
I can't have sucked you can't have sucked he can't have sucked we can't have sucked you can't have sucked they can't have sucked
V-ing perfect
I can't have been sucking you can't have been sucking he can't have been sucking we can't have been sucking you can't have been sucking they can't have been sucking
Interrogative form
Simple form
can I suck? can you suck? can he suck? can we suck? can you suck? can they suck?
V-ing form
can I be sucking? can you be sucking? can he be sucking? can we be sucking? can you be sucking? can they be sucking?
Perfect
can I have sucked? can you have sucked? can he have sucked? can we have sucked? can you have sucked? can they have sucked?
V-ing perfect
can I have been sucking? can you have been sucking? can he have been sucking? can we have been sucking? can you have been sucking? can they have been sucking?
Interro-negative form
Simple form
can't I suck? can't you suck? can't he suck? can't we suck? can't you suck? can't they suck?
V-ing form
can't I be sucking? can't you be sucking? can't he be sucking? can't we be sucking? can't you be sucking? can't they be sucking?
Perfect
can't I have sucked? can't you have sucked? can't he have sucked? can't we have sucked? can't you have sucked? can't they have sucked?
V-ing perfect
can't I have been sucking? can't you have been sucking? can't he have been sucking? can't we have been sucking? can't you have been sucking? can't they have been sucking?