I can winnow you can winnow he can winnow we can winnow you can winnow they can winnow
V-ing form
I can be winnowing you can be winnowing he can be winnowing we can be winnowing you can be winnowing they can be winnowing
Perfect
I can have winnowed you can have winnowed he can have winnowed we can have winnowed you can have winnowed they can have winnowed
V-ing perfect
I can have been winnowing you can have been winnowing he can have been winnowing we can have been winnowing you can have been winnowing they can have been winnowing
Negation
Simple form
I cannot winnow you cannot winnow he cannot winnow we cannot winnow you cannot winnow they cannot winnow
V-ing form
I cannot be winnowing you cannot be winnowing he cannot be winnowing we cannot be winnowing you cannot be winnowing they cannot be winnowing
Perfect
I cannot have winnowed you cannot have winnowed he cannot have winnowed we cannot have winnowed you cannot have winnowed they cannot have winnowed
V-ing perfect
I cannot have been winnowing you cannot have been winnowing he cannot have been winnowing we cannot have been winnowing you cannot have been winnowing they cannot have been winnowing
Interrogative form
Simple form
can I winnow? can you winnow? can he winnow? can we winnow? can you winnow? can they winnow?
V-ing form
can I be winnowing? can you be winnowing? can he be winnowing? can we be winnowing? can you be winnowing? can they be winnowing?
Perfect
can I have winnowed? can you have winnowed? can he have winnowed? can we have winnowed? can you have winnowed? can they have winnowed?
V-ing perfect
can I have been winnowing? can you have been winnowing? can he have been winnowing? can we have been winnowing? can you have been winnowing? can they have been winnowing?
Interro-negative form
Simple form
can I not winnow? can you not winnow? can he not winnow? can we not winnow? can you not winnow? can they not winnow?
V-ing form
can I not be winnowing? can you not be winnowing? can he not be winnowing? can we not be winnowing? can you not be winnowing? can they not be winnowing?
Perfect
can I not have winnowed? can you not have winnowed? can he not have winnowed? can we not have winnowed? can you not have winnowed? can they not have winnowed?
V-ing perfect
can I not have been winnowing? can you not have been winnowing? can he not have been winnowing? can we not have been winnowing? can you not have been winnowing? can they not have been winnowing?