I know that you are an authority ___the subject.
                    举一反三
- What I mean is that you should gain the ability to learn a new subject.
 - “Why are you working so hard at math?” “I do wish I _______ more about the subject.”
 - As we know, the books in the library are by subject.
 - —I must apologize for_____________ ahead of time—That’s all right. A: letting you not know B: not letting you know C: letting you know not D: letting not you know
 - Had I know the result, I you to tell me.
 
