About ＿ of the class know something about their grandparents.
举一反三
- About three-fourths of the class know something about their great-grandparents.
- Know something about the organization you are applying for.
- You’d better know something about how to ______ to an invitation._
- Why we have to know something about the Western holidays?
- If you know the of something, you know all the details about it and understand how it works.