Thank you for your check. I wrote “a staff member” in another letter, and a Teacher also changed it to “one of staff members”. I think there is no grammar mistake. Could you tell me the subtle difference between the two phrases? And could I write “one of your hotel staff”?
. . . all of us recalled the happy time we had . . . / . . . all of us thought of the happy time we were having . . .
I’m sorry. I think that the two clauses express similar meaning, that is, we had happy time and when we heard Ms. Smith’s song at the party, we remembered it again. I do not know whether I understand it right or not. Could you make it more clearly?