Question

what I need _book(s) 请问横线上是is还是are？ 那what we need

what I need _book(s)
请问横线上是is还是are？
那what we need_book(s)呢？

Answer 1

都用is

Answer 2

are

追答

如果是books的话。

如果是a book, 那就是：What we need is a book.

主语从句一般来说作主语，谓语动词用单数。但是表语如果是复数（books) 时，谓语动词be要用复数are！

Answer 3

当从句出现在主语中时,主句的谓语动词用单数形式例如：
What is done is done.
What is gone is gone.
当从句是个带有复数意义的并列结构时,主句的谓语动词用复数形式。例如：
What I say and think are no business of yours. (= What I say is… and what I think is…)
故第一题应该选is 第二题选are