I can substitute you can substitute she can substitute we can substitute you can substitute they can substitute
V-ing form
I can be substituting you can be substituting she can be substituting we can be substituting you can be substituting they can be substituting
Perfect
I can have substituted you can have substituted she 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 she 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 she 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 she 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 she 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 she 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 she substitute? can we substitute? can you substitute? can they substitute?
V-ing form
can I be substituting? can you be substituting? can she be substituting? can we be substituting? can you be substituting? can they be substituting?
Perfect
can I have substituted? can you have substituted? can she 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 she 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 she 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 she 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 she 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 she have been substituting? can't we have been substituting? can't you have been substituting? can't they have been substituting?