Hi Yeonghyeon,
You already asked this question here:
https://forums.autodesk.com/t5/autocad-for-mac-forum/how-to-solve-a-broken-font-text-in-the-preview/...And didn't respond to my questions for some reason.
For now I want to ask you another one:
What do you mean by it is "broken"? I cannot understand this from screenshots you provided.