It may ________ branding issues, control, or job security; we just don't know.
举一反三
- It ______________ to know what you don’t know.
- I just don’t know how we’ve managed to ______ so much junk!
- ﹣Do you know the man ____________ spoke at the meeting just now？ ﹣ No， I donˈt know． A: what B: who C: which D: whose
- It is good for you to know what you don’t know. (pay)
- 中国大学MOOC: It ______________ to know what you don’t know.