Sentence:  By the time Felix turned up it was early afternoon , which , one would think , would be late enough so that by <WSD>then</WSD> , except for small children and a few hardy souls who had not yet sobered up , it could have been expected that people would no longer be having any sort of active interest in the previous night 's noisemakers and paper hats . 
Meaning of the word marked with <WSD> tags:  at that time