The meanings of ranks in the figure are as follows: (A) Perfect: no problem in both information and grammar; (B) Fair: easyto-understand with some unimportant information missing or flawed grammar; (C) Acceptable: broken but understandable with effort; (D) Nonsense: important information has been translated incorrectly.
for the utterance unit evaluation, we conducted several experiments while varying N from 1 to 4 for BLEU and from 1 to 5 for NIST.