half of...和 some of...的主谓一致问题

Half of the class__________ most of the work, and some of the work__________ difficult.

A. has done, is B. have done, is C. has done, are D. have done, are

如何看是half of the class 是强调整体还是个体呢？好像都可以讲解！

Half of the class have done most of the work, and some of the work is difficult.

the class 指“全班同学” ，是复数定义。