subjects,from,to,question,answer
common.hello,question,answer,how are you,I'm good... I hope you are too.
common.hello,question,answer,How are you doing,I'm good... I hope you are too.
common.hello,question,answer,Hello!,Hello!
common.hello,question,answer,Good afternoon,Good afternoon!
common.hello,question,answer,Good evening,Good evening!