I can commemorate you can commemorate he can commemorate we can commemorate you can commemorate they can commemorate
V-ing form
I can be commemorating you can be commemorating he can be commemorating we can be commemorating you can be commemorating they can be commemorating
Perfect
I can have commemorated you can have commemorated he can have commemorated we can have commemorated you can have commemorated they can have commemorated
V-ing perfect
I can have been commemorating you can have been commemorating he can have been commemorating we can have been commemorating you can have been commemorating they can have been commemorating
Negation
Simple form
I can't commemorate you can't commemorate he can't commemorate we can't commemorate you can't commemorate they can't commemorate
V-ing form
I can't be commemorating you can't be commemorating he can't be commemorating we can't be commemorating you can't be commemorating they can't be commemorating
Perfect
I can't have commemorated you can't have commemorated he can't have commemorated we can't have commemorated you can't have commemorated they can't have commemorated
V-ing perfect
I can't have been commemorating you can't have been commemorating he can't have been commemorating we can't have been commemorating you can't have been commemorating they can't have been commemorating
Interrogative form
Simple form
can I commemorate? can you commemorate? can he commemorate? can we commemorate? can you commemorate? can they commemorate?
V-ing form
can I be commemorating? can you be commemorating? can he be commemorating? can we be commemorating? can you be commemorating? can they be commemorating?
Perfect
can I have commemorated? can you have commemorated? can he have commemorated? can we have commemorated? can you have commemorated? can they have commemorated?
V-ing perfect
can I have been commemorating? can you have been commemorating? can he have been commemorating? can we have been commemorating? can you have been commemorating? can they have been commemorating?
Interro-negative form
Simple form
can't I commemorate? can't you commemorate? can't he commemorate? can't we commemorate? can't you commemorate? can't they commemorate?
V-ing form
can't I be commemorating? can't you be commemorating? can't he be commemorating? can't we be commemorating? can't you be commemorating? can't they be commemorating?
Perfect
can't I have commemorated? can't you have commemorated? can't he have commemorated? can't we have commemorated? can't you have commemorated? can't they have commemorated?
V-ing perfect
can't I have been commemorating? can't you have been commemorating? can't he have been commemorating? can't we have been commemorating? can't you have been commemorating? can't they have been commemorating?