I can study you can study she can study we can study you can study they can study
V-ing form
I can be studying you can be studying she can be studying we can be studying you can be studying they can be studying
Perfect
I can have studied you can have studied she can have studied we can have studied you can have studied they can have studied
V-ing perfect
I can have been studying you can have been studying she can have been studying we can have been studying you can have been studying they can have been studying
Negation
Simple form
I can't study you can't study she can't study we can't study you can't study they can't study
V-ing form
I can't be studying you can't be studying she can't be studying we can't be studying you can't be studying they can't be studying
Perfect
I can't have studied you can't have studied she can't have studied we can't have studied you can't have studied they can't have studied
V-ing perfect
I can't have been studying you can't have been studying she can't have been studying we can't have been studying you can't have been studying they can't have been studying
Interrogative form
Simple form
can I study? can you study? can she study? can we study? can you study? can they study?
V-ing form
can I be studying? can you be studying? can she be studying? can we be studying? can you be studying? can they be studying?
Perfect
can I have studied? can you have studied? can she have studied? can we have studied? can you have studied? can they have studied?
V-ing perfect
can I have been studying? can you have been studying? can she have been studying? can we have been studying? can you have been studying? can they have been studying?
Interro-negative form
Simple form
can't I study? can't you study? can't she study? can't we study? can't you study? can't they study?
V-ing form
can't I be studying? can't you be studying? can't she be studying? can't we be studying? can't you be studying? can't they be studying?
Perfect
can't I have studied? can't you have studied? can't she have studied? can't we have studied? can't you have studied? can't they have studied?
V-ing perfect
can't I have been studying? can't you have been studying? can't she have been studying? can't we have been studying? can't you have been studying? can't they have been studying?