Because this reason:
I rewrite this function in qa-util-string.php , to return a new string after filter.
function qa_block_words_replace($string, $wordspreg, $character='*')
I find that this function can return a string replace each censored word with a *(like "平安" to "*", I don't know if it is requried to return not only one *). But on the website page,the censored words appears always.
Should I do more things?