Thanks for your answer ou!
however, when i use "quick Chinese input" and tried to right click the icon, the option of OSK doesn't appear...it just show:
Is that normal in win8.1? it's weird to me!!
p.s. I won't be using 觸控式鍵盤 as I would physically type the real keyboard and clicking the screen keyboard the same time...so when I type the real keyboard, the 觸控式鍵盤 disappear...