系动词：be seem appear sound feel look smell taste get become come go prove turn
情态动词：can, could, may, might ,will, would ,shall ,should ,must ,need ,dare ,ought to ,used to 还有情态短语：had better,would rather/sooner,be to
助词：be(am,is,are),have,do 及它们的过去式.还有半助动词
以上只是列出来了,没有解释.