I can decay you can decay he can decay we can decay you can decay they can decay
V-ing form
I can be decaying you can be decaying he can be decaying we can be decaying you can be decaying they can be decaying
Perfect
I can have decayed you can have decayed he can have decayed we can have decayed you can have decayed they can have decayed
V-ing perfect
I can have been decaying you can have been decaying he can have been decaying we can have been decaying you can have been decaying they can have been decaying
Negation
Simple form
I can't decay you can't decay he can't decay we can't decay you can't decay they can't decay
V-ing form
I can't be decaying you can't be decaying he can't be decaying we can't be decaying you can't be decaying they can't be decaying
Perfect
I can't have decayed you can't have decayed he can't have decayed we can't have decayed you can't have decayed they can't have decayed
V-ing perfect
I can't have been decaying you can't have been decaying he can't have been decaying we can't have been decaying you can't have been decaying they can't have been decaying
Interrogative form
Simple form
can I decay? can you decay? can he decay? can we decay? can you decay? can they decay?
V-ing form
can I be decaying? can you be decaying? can he be decaying? can we be decaying? can you be decaying? can they be decaying?
Perfect
can I have decayed? can you have decayed? can he have decayed? can we have decayed? can you have decayed? can they have decayed?
V-ing perfect
can I have been decaying? can you have been decaying? can he have been decaying? can we have been decaying? can you have been decaying? can they have been decaying?
Interro-negative form
Simple form
can't I decay? can't you decay? can't he decay? can't we decay? can't you decay? can't they decay?
V-ing form
can't I be decaying? can't you be decaying? can't he be decaying? can't we be decaying? can't you be decaying? can't they be decaying?
Perfect
can't I have decayed? can't you have decayed? can't he have decayed? can't we have decayed? can't you have decayed? can't they have decayed?
V-ing perfect
can't I have been decaying? can't you have been decaying? can't he have been decaying? can't we have been decaying? can't you have been decaying? can't they have been decaying?