I can shell you can shell he can shell we can shell you can shell they can shell
V-ing form
I can be shelling you can be shelling he can be shelling we can be shelling you can be shelling they can be shelling
Perfect
I can have shelled you can have shelled he can have shelled we can have shelled you can have shelled they can have shelled
V-ing perfect
I can have been shelling you can have been shelling he can have been shelling we can have been shelling you can have been shelling they can have been shelling
Negation
Simple form
I cannot shell you cannot shell he cannot shell we cannot shell you cannot shell they cannot shell
V-ing form
I cannot be shelling you cannot be shelling he cannot be shelling we cannot be shelling you cannot be shelling they cannot be shelling
Perfect
I cannot have shelled you cannot have shelled he cannot have shelled we cannot have shelled you cannot have shelled they cannot have shelled
V-ing perfect
I cannot have been shelling you cannot have been shelling he cannot have been shelling we cannot have been shelling you cannot have been shelling they cannot have been shelling
Interrogative form
Simple form
can I shell? can you shell? can he shell? can we shell? can you shell? can they shell?
V-ing form
can I be shelling? can you be shelling? can he be shelling? can we be shelling? can you be shelling? can they be shelling?
Perfect
can I have shelled? can you have shelled? can he have shelled? can we have shelled? can you have shelled? can they have shelled?
V-ing perfect
can I have been shelling? can you have been shelling? can he have been shelling? can we have been shelling? can you have been shelling? can they have been shelling?
Interro-negative form
Simple form
can I not shell? can you not shell? can he not shell? can we not shell? can you not shell? can they not shell?
V-ing form
can I not be shelling? can you not be shelling? can he not be shelling? can we not be shelling? can you not be shelling? can they not be shelling?
Perfect
can I not have shelled? can you not have shelled? can he not have shelled? can we not have shelled? can you not have shelled? can they not have shelled?
V-ing perfect
can I not have been shelling? can you not have been shelling? can he not have been shelling? can we not have been shelling? can you not have been shelling? can they not have been shelling?