By adding modifying phrases to the end of a sentence, a writer can take the reader in new, sometimes unexpected directions. A resumptive modifier picks up a word or phrase from a sentence that seems to be finished and then adds information and takes the reader into new territory of thought. Because resumptive modifiers are, by nature, repetitive, they tend also to add a sense of rhythm to a sentence. The following sentence (borrowed from above) employs this strategy twice:
The Swiss watchmakers' failure to capitalize on the invention of the digital timepiece was both astonishing and alarming — astonishing in that the Swiss had, since the beginnings of the industrial revolution in Europe, been among the first to capitalize on technical innovations, alarming in that a tremendous industrial potential had been lost to their chief competitors, the watchmakers of Japan.
A summative modifier quickly re-names or sums up what was going on in an earlier part of the sentence and then adds new information:
The defensive coaches taught risk-taking, ball-hawking, and perpetual movement — three strategies that bewildered the opposition and resulted in many bad passes, steals, and easy fastbreak baskets.