Sentence:  There is only one sure way to memorise the runs and that is to follow them, either on foot, cycle or motor cycle; hence, the familiar sight of would-be cabbies learning the <WSD>knowledge</WSD> during evenings and weekends. 
Meaning of the word marked with <WSD> tags:  The deep familiarity with certain routes and places of interest required by taxicab drivers working in London, England.