half of the class___most of the work,some of the work___really difficult

问题描述:

half of the class___most of the work,some of the work___really difficult
Ahave done,is Bhad done,are Chas done,is Dhave done,are

A
前面的class指的是班级同学,是复数;后面的some of the work是指整体工作的一部分,应该是单数.