【正文】 =========Dear Editor,I quite appreciate your favorite consideration and the reviewer’s insightful ments. Now I have revised the JCIS06247 exactly according to the reviewer’s ments, and found these ments are very helpful. I hope this revision can make my paper more acceptable. The revisions were addressed point by point below.[general] The objective of this research was added at the beginning of the third paragraph of Introduction. How the study is useful for practical purposes was added at the end of Conclusion as one paragraph.[1] Ambiguous statement ., “much work is still ahead” was deleted.[2] Ethyl pyruvate was used here as a typical pound (containing two carbonyl groups) to demonstrate the feasibility of using our diagnosing tool to detect lowcoverage CO (ing from decarbonylation of EtPy) at the liquidsolid interface. EtPy is a reactant used in liquidphase chiral catalysis, and slight deposition of EtPy to adsorbed CO was reported to influence the catalytic performance. In addition, by studying that, we can directly pare our results with previous studies. More details in the first paragraph of Section .[3] The IR cell was designed according to the IR cells used by many electrochemical workers. References were added. A photo was given in the Supporting Information.[4] A flow diagram of the experimental setup was given in the new Fig. 1.[5] The CO adsorption experiments were performed in the same adsorption mode, by bubbling CO through a clean Pt surface in different days to achieve the same saturation coverage of CO. Initial experiments indicated that given the CO bubbling rate was cm3/min, CO can saturate on Pt after 3045 min. We bubble CO for 60 min to guarantee the same CO coverage. If we bubble CO for more time, or if we increase the CO flowing rate several times, the CO saturation coverage doesn’t change, indicating 60 min is already enough. A figure showing the CO uptake as a function of bubbling time was given in the Supporting Information.[6] The displaceme