hi,yiming
with my poor english ,i guess your meaning is: in a whole English book,a few chinese words can be correctly show，but in my test:
the Chinese Edition《Steve Jobs:A Biography》 ,when its title is Chinese, the format in txt/epub,the book is "???" ;when its title is English ,the txt/epub also "???".
and for the mobi,if i change a chinese book'titel into English ,it's also only "???".
i don't konw why~~