Punctuation marks in utterances including the phrase и ( вот / тогда / теперь) я думаю ‘ and ( then / now / so) I think’

The article describes the rules of punctuation mark usage in the utterances containing the phrase И я думаю ‘ And I think ’. The material for the analysis is the phrase usage in the text of 2013Total Dictation Campaign. The author reviews punctuation rules referring to this case in Russian stylebooks as well as data of Russian National Corpus wherein the phrase may include the words then / now / so.