I can flush you can flush he can flush we can flush you can flush they can flush
V-ing form
I can be flushing you can be flushing he can be flushing we can be flushing you can be flushing they can be flushing
Perfect
I can have flushed you can have flushed he can have flushed we can have flushed you can have flushed they can have flushed
V-ing perfect
I can have been flushing you can have been flushing he can have been flushing we can have been flushing you can have been flushing they can have been flushing
Negation
Simple form
I cannot flush you cannot flush he cannot flush we cannot flush you cannot flush they cannot flush
V-ing form
I cannot be flushing you cannot be flushing he cannot be flushing we cannot be flushing you cannot be flushing they cannot be flushing
Perfect
I cannot have flushed you cannot have flushed he cannot have flushed we cannot have flushed you cannot have flushed they cannot have flushed
V-ing perfect
I cannot have been flushing you cannot have been flushing he cannot have been flushing we cannot have been flushing you cannot have been flushing they cannot have been flushing
Interrogative form
Simple form
can I flush? can you flush? can he flush? can we flush? can you flush? can they flush?
V-ing form
can I be flushing? can you be flushing? can he be flushing? can we be flushing? can you be flushing? can they be flushing?
Perfect
can I have flushed? can you have flushed? can he have flushed? can we have flushed? can you have flushed? can they have flushed?
V-ing perfect
can I have been flushing? can you have been flushing? can he have been flushing? can we have been flushing? can you have been flushing? can they have been flushing?
Interro-negative form
Simple form
can I not flush? can you not flush? can he not flush? can we not flush? can you not flush? can they not flush?
V-ing form
can I not be flushing? can you not be flushing? can he not be flushing? can we not be flushing? can you not be flushing? can they not be flushing?
Perfect
can I not have flushed? can you not have flushed? can he not have flushed? can we not have flushed? can you not have flushed? can they not have flushed?
V-ing perfect
can I not have been flushing? can you not have been flushing? can he not have been flushing? can we not have been flushing? can you not have been flushing? can they not have been flushing?