sentences:  In the series finale, actor Felix Lok ad-libbed one of his lines, and replaced one of the words in the line with a corresponding English one.Although code-switching has been very common in Hong Kong as of the last 10–20 years, such practice is unheard of for the time period of the drama, and, in most circumstances, unlikely, considering the historically non-existent knowledge of English for the characters.TVB was ridiculed by the public for allowing such a slip up.