问题补充：
---Is Sarah coming ?
--- No. She should have let us know earlier , but she has been very busy recently.
A. to be sure
B. to be honest
C. to be fair
D. to be exact
答案：
A. to be sure
B. to be honest
(答案→)C. to be fair
D. to be exact
解析：句意：莎拉来了吗？没有，她本应该早让我们知道的，但是，说句公道话，她最经一直非常忙。to be fair说句公道话，to be honest老实说，to be sure诚然，to be exact确切的说，故选C
