英语中,当what引导的名词性从句作主语时, 主句的谓语动词（一般为be的某种形式）有时用单数形式，有时又用复数形式。如何处理这种主谓一致关系？下面就对这一问题作了些归纳与整理。

1．在what引导名词性从句作主语时的SVC (即“主语+谓语动词+表语”)结构中,如果主语补语是单数名词或不可数名词,主句的谓语动词采取单数形式。

例如：

　　What the boy wants is a toy car.

　　What the country needs most is wise leadership.

2．当主句的表语是复数名词时,主句的谓语动词通常用复数形式。

例如：

　　What we need are good doctors.

　　What was real to him were the details of his life.

　　但在美国英语中主句的谓语动词也可以用单数形式：

　　Perhaps what is most surprising is the tears.

　　What we getting is old answers to old questions. 

3. 当从句的谓语动词和主句的表语均为复数形式时, 主句的谓语动词一般要用复数形式。

例如：

　　What have surfaced are similes, viscous streams of them.

　　What are often regarded as poisonous fungi are sometimes safely edible.

4．当主句的表语是形容词时,谓语动词通常用单数形式。

例如：

　　What is beautiful is not always good.

　　What I have to tell you is very simple.

　　但当从句的what修饰复数名词时，主句的谓语动词就用复数形式：

　　What friends she has are clever.

5．当主句的表语是介词短语时,谓语动词用单数形式。

例如：

　　What they did was in vain.

　　What the students do in their spare time is of great importance.

6．当从句出现在成语中时,主句的谓语动词用单数形式。

例如：

　　What is done is done.

　　What is gone is gone.

7．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…)

　　如果从句是个带有单数意义的并列结构,主句的谓语动词就用单数形式：

　　What he willed and ordered was law amongst his clan and family.

8．著名学者周海中教授在1985年发表的《关于what-分句作主语的主谓一致问题》一文中指出：当主句的表语是动词不定式、动词V-ing和从句时, 谓语动词用单数形式。

他给出了以下的实例：

　　What he is suited for is to be loved. (J. Bayley: Shakespeare and Tragedy)

　　What we're doing is getting a chap used to getting up, going to work, learning how to behave in a workshop. (New Statesman, 15 June 1984)

　　What it comes down to is that the big cars are considered better buys. (U. S. News & World Report, January 18, 1982)