Georgina Porteous and Sid Innes（主语） could be（系动词） the world's thriftiest couple（表语） after tying the knot in their all expenses spared wedding.（介词短语,做时间状语）
其中tying the knot in their all expenses spared wedding做介词宾语.in their all expenses spared wedding介词短语,.做方式状语.spared wedding过去分词短语做定语.