they have finished a large part of the work andhe rest more difficultA,is B,are C,was D,were

问题描述:

they have finished a large part of the work and
he rest more difficult
A,is B,are C,was D,were

A
由于指work “工作”,the rest "其余的“要接单数谓语
前文是现在完成时,所以排除过去式was