be动词填空 how much ----- the exercise book and the magazine?That ------ninety dollars.

题目

be动词填空 how much ----- the exercise book and the magazine?That ------ninety dollars.
am is are应该填?

答案

1.are 主语是后面的书和杂志,是复数,所以用are
2.is 主语是that,表单数,用is