I can ponder you can ponder she can ponder we can ponder you can ponder they can ponder
V-ing form
I can be pondering you can be pondering she can be pondering we can be pondering you can be pondering they can be pondering
Perfect
I can have pondered you can have pondered she can have pondered we can have pondered you can have pondered they can have pondered
V-ing perfect
I can have been pondering you can have been pondering she can have been pondering we can have been pondering you can have been pondering they can have been pondering
Negation
Simple form
I cannot ponder you cannot ponder she cannot ponder we cannot ponder you cannot ponder they cannot ponder
V-ing form
I cannot be pondering you cannot be pondering she cannot be pondering we cannot be pondering you cannot be pondering they cannot be pondering
Perfect
I cannot have pondered you cannot have pondered she cannot have pondered we cannot have pondered you cannot have pondered they cannot have pondered
V-ing perfect
I cannot have been pondering you cannot have been pondering she cannot have been pondering we cannot have been pondering you cannot have been pondering they cannot have been pondering
Interrogative form
Simple form
can I ponder? can you ponder? can she ponder? can we ponder? can you ponder? can they ponder?
V-ing form
can I be pondering? can you be pondering? can she be pondering? can we be pondering? can you be pondering? can they be pondering?
Perfect
can I have pondered? can you have pondered? can she have pondered? can we have pondered? can you have pondered? can they have pondered?
V-ing perfect
can I have been pondering? can you have been pondering? can she have been pondering? can we have been pondering? can you have been pondering? can they have been pondering?
Interro-negative form
Simple form
can I not ponder? can you not ponder? can she not ponder? can we not ponder? can you not ponder? can they not ponder?
V-ing form
can I not be pondering? can you not be pondering? can she not be pondering? can we not be pondering? can you not be pondering? can they not be pondering?
Perfect
can I not have pondered? can you not have pondered? can she not have pondered? can we not have pondered? can you not have pondered? can they not have pondered?
V-ing perfect
can I not have been pondering? can you not have been pondering? can she not have been pondering? can we not have been pondering? can you not have been pondering? can they not have been pondering?