一道现在完成时用法的题

dandan74

77. Though the term "graphic design" may suggest laying out corporate brochures and annual reports, they have come to signify widely ranging work, from package designs and company logotypes to signs, book jackets, computer graphics, and film titles.
(A)    suggest laying out corporate brochures and annual reports, they have come to signify widely ranging
(B)    suggest laying out corporate brochures and annual reports, it has come to signify a wide range of
(C)    suggest corporate brochure and annual report layout, it has signified widely ranging
(D)    have suggested corporate brochure and annual report layout, it has signified a wide range of
(E)    have suggested laying out corporate brochures and annual reports, they have come to signify widely ranging

这道题OG的解释是：
The present perfect tense is used inappropriately in choices C (has signified), D (have suggested... has signified), and E (have suggested) to indicate recently completed rather than ongoing action.
我的疑问是：现在完成时不是表示一个动作一直持续到现在，而不一定完成吗？为什莫这里不能表示on-going的situation呢?

dandan74

up!

trifen

现在完成时所表示的动作可以为过去完成的动作，比如过去完成的动作对现在的影响。