I can substitute you can substitute he can substitute we can substitute you can substitute they can substitute
V-ing form
I can be substituting you can be substituting he can be substituting we can be substituting you can be substituting they can be substituting
Perfect
I can have substituted you can have substituted he can have substituted we can have substituted you can have substituted they can have substituted
V-ing perfect
I can have been substituting you can have been substituting he can have been substituting we can have been substituting you can have been substituting they can have been substituting
Negation
Simple form
I can't substitute you can't substitute he can't substitute we can't substitute you can't substitute they can't substitute
V-ing form
I can't be substituting you can't be substituting he can't be substituting we can't be substituting you can't be substituting they can't be substituting
Perfect
I can't have substituted you can't have substituted he can't have substituted we can't have substituted you can't have substituted they can't have substituted
V-ing perfect
I can't have been substituting you can't have been substituting he can't have been substituting we can't have been substituting you can't have been substituting they can't have been substituting
Interrogative form
Simple form
can I substitute? can you substitute? can he substitute? can we substitute? can you substitute? can they substitute?
V-ing form
can I be substituting? can you be substituting? can he be substituting? can we be substituting? can you be substituting? can they be substituting?
Perfect
can I have substituted? can you have substituted? can he have substituted? can we have substituted? can you have substituted? can they have substituted?
V-ing perfect
can I have been substituting? can you have been substituting? can he have been substituting? can we have been substituting? can you have been substituting? can they have been substituting?
Interro-negative form
Simple form
can't I substitute? can't you substitute? can't he substitute? can't we substitute? can't you substitute? can't they substitute?
V-ing form
can't I be substituting? can't you be substituting? can't he be substituting? can't we be substituting? can't you be substituting? can't they be substituting?
Perfect
can't I have substituted? can't you have substituted? can't he have substituted? can't we have substituted? can't you have substituted? can't they have substituted?
V-ing perfect
can't I have been substituting? can't you have been substituting? can't he have been substituting? can't we have been substituting? can't you have been substituting? can't they have been substituting?