Such poets as Shakespeare ________ widely read, of whose works, however, some ________ difficult to understand.
句意：像莎士比亚这样的诗人的作品读的人很多，然而，作 品中有一些很难懂。主句中的主语应为poets，谓语动词用复数，其后的非限制性定语从句的主语为some of whose works，谓语动词也应是复数。