What I want to say is highly subjective. I would agree with what others have said about singular vs. plural in the abstract. But here, we have a context: When HE SPOKE I was expected to RECIPROCATE. A "remark" is something brief that a person says. A remark is usually only a few words, and it usually takes seconds or only a minute to make it. In this context, if we say that someone "spoke" about something which was so important and meaningful that another person was expected to "reciprocate," it would seem odd to me that the second person could "reciprocate" by merely making a "remark" (i.e., saying just a few words which take only seconds or a minute to say). That would hardly amount to reciprocation. The second person is expected to "reciprocate" -- i.e, he's expected to say something of more or less the same value. He would make a number of remarks touching or responding to different aspects of what the first person said. So I would say, "When he spoke, I was expected to reciprocate with some remarks of my own."

It really depends on whether you want to make only one remark or more than one remark. If you want to just make one remark, then you could say "Let me make some remark." (I, personally, would prefer using "Let me make a remark.") The "some" here indicates that you are going to make some kind of remark, a certain remark. If you want to make more than one remark, it would be better to say "Let me make some remarks," since it's plural. Please feel free to message me directly with any other questions.

Hello, chinesespeakerhy, This is simply an issue of singular vs. plural. If the person made one remark, it's singular; if he/she made more than one, it's plural. However, I'm guessing that the confusion comes from the usage of the word "some." In this context, "some" does not necessarily mean "more than one." Instead, it means "unspecified." Thus, if I was expected to respond with "some remark" about the issue, it means that I should have responded with a general remark of my own related to the issue. I hope this helps. Please let me know if my answer is confusing.