I can stockpile you can stockpile he can stockpile we can stockpile you can stockpile they can stockpile
V-ing form
I can be stockpiling you can be stockpiling he can be stockpiling we can be stockpiling you can be stockpiling they can be stockpiling
Perfect
I can have stockpiled you can have stockpiled he can have stockpiled we can have stockpiled you can have stockpiled they can have stockpiled
V-ing perfect
I can have been stockpiling you can have been stockpiling he can have been stockpiling we can have been stockpiling you can have been stockpiling they can have been stockpiling
Negation
Simple form
I cannot stockpile you cannot stockpile he cannot stockpile we cannot stockpile you cannot stockpile they cannot stockpile
V-ing form
I cannot be stockpiling you cannot be stockpiling he cannot be stockpiling we cannot be stockpiling you cannot be stockpiling they cannot be stockpiling
Perfect
I cannot have stockpiled you cannot have stockpiled he cannot have stockpiled we cannot have stockpiled you cannot have stockpiled they cannot have stockpiled
V-ing perfect
I cannot have been stockpiling you cannot have been stockpiling he cannot have been stockpiling we cannot have been stockpiling you cannot have been stockpiling they cannot have been stockpiling
Interrogative form
Simple form
can I stockpile? can you stockpile? can he stockpile? can we stockpile? can you stockpile? can they stockpile?
V-ing form
can I be stockpiling? can you be stockpiling? can he be stockpiling? can we be stockpiling? can you be stockpiling? can they be stockpiling?
Perfect
can I have stockpiled? can you have stockpiled? can he have stockpiled? can we have stockpiled? can you have stockpiled? can they have stockpiled?
V-ing perfect
can I have been stockpiling? can you have been stockpiling? can he have been stockpiling? can we have been stockpiling? can you have been stockpiling? can they have been stockpiling?
Interro-negative form
Simple form
can I not stockpile? can you not stockpile? can he not stockpile? can we not stockpile? can you not stockpile? can they not stockpile?
V-ing form
can I not be stockpiling? can you not be stockpiling? can he not be stockpiling? can we not be stockpiling? can you not be stockpiling? can they not be stockpiling?
Perfect
can I not have stockpiled? can you not have stockpiled? can he not have stockpiled? can we not have stockpiled? can you not have stockpiled? can they not have stockpiled?
V-ing perfect
can I not have been stockpiling? can you not have been stockpiling? can he not have been stockpiling? can we not have been stockpiling? can you not have been stockpiling? can they not have been stockpiling?