question: private String extractSpan ( String spans , int start , int end ) throws IndexOutOfBoundsException { int offset = getFirstSpanOffset ( spans ) ; assert ( start >= offset ) ; assert ( end >= offset ) ; spans += HTML_OPEN_SPAN ; int substart = getSpanPos ( spans , start - offset ) ; int subend = getSpanPos ( spans , end - offset + 1 ) ; return spans . substring ( substart , subend ) ; }
target:  Helper function for uploadNewNERTask2: Extract certain token spans from the HTML token spans that the Crowdflower job task1 uses to display a text fragment. It is used to cut out a named entity from HTML token spans.