YOU SAID:
My dog ran really fast today
INTO JAPANESE
今日私の犬は本当に速く走った
BACK INTO ENGLISH
Today my dog ran really fast
INTO JAPANESE
今日、私の犬は本当に速く走った
BACK INTO ENGLISH
Today, my dog ran really fast
INTO JAPANESE
今日、私の犬は本当に速く走った
BACK INTO ENGLISH
Today, my dog ran really fast
You've done this before, haven't you.