I can start you can start he can start we can start you can start they can start
V-ing form
I can be starting you can be starting he can be starting we can be starting you can be starting they can be starting
Perfect
I can have started you can have started he can have started we can have started you can have started they can have started
V-ing perfect
I can have been starting you can have been starting he can have been starting we can have been starting you can have been starting they can have been starting
Negation
Simple form
I can't start you can't start he can't start we can't start you can't start they can't start
V-ing form
I can't be starting you can't be starting he can't be starting we can't be starting you can't be starting they can't be starting
Perfect
I can't have started you can't have started he can't have started we can't have started you can't have started they can't have started
V-ing perfect
I can't have been starting you can't have been starting he can't have been starting we can't have been starting you can't have been starting they can't have been starting
Interrogative form
Simple form
can I start? can you start? can he start? can we start? can you start? can they start?
V-ing form
can I be starting? can you be starting? can he be starting? can we be starting? can you be starting? can they be starting?
Perfect
can I have started? can you have started? can he have started? can we have started? can you have started? can they have started?
V-ing perfect
can I have been starting? can you have been starting? can he have been starting? can we have been starting? can you have been starting? can they have been starting?
Interro-negative form
Simple form
can't I start? can't you start? can't he start? can't we start? can't you start? can't they start?
V-ing form
can't I be starting? can't you be starting? can't he be starting? can't we be starting? can't you be starting? can't they be starting?
Perfect
can't I have started? can't you have started? can't he have started? can't we have started? can't you have started? can't they have started?
V-ing perfect
can't I have been starting? can't you have been starting? can't he have been starting? can't we have been starting? can't you have been starting? can't they have been starting?