主谓一致是语法考试的一大重点，无论是我们国内的中考还是高考，还是国外的标准化考试中的语法部分，都占有非常重要的地位。因此，主谓一致必然也成了ACT语法考试的一部分了。但是，作为美国高考，对于主谓一致的考察也更加复杂。

　　1.定语从句内部的谓语，取决于定语从句的先行词：

　　如：Early rock and roll music like jazz and blues, celebrated characteristics of urban life that was once only disparaged.

　　that was once only disparaged是该句中的定语从句，这个定语从句修饰的是urban life，从句中的主语that也是指的urban life，所以谓语应该与之一致，用was。

　　例4：71C65

　　Even though these groups of animals are only distantly related, they have similarities in brain structure that accounts for the shared vocal learning ability.

　　A. NO CHANGE

　　B. Of which accounts

　　C. Of which account

　　D. that account

　　【答案】D

　　【解析】出题点在定语从句that accounts for the shared vocal learning ability中，而这里的that是指similarities? 还是 brain structure呢?我们看从句的意思"这就解释了共同的语音学习能力"，所以说，这个定语从句是修饰similarities的，所以谓语用复数，选D

　　2.宾语从句中，主句和从句的主干要分清

　　例5：72C8

　　In 2009, Libbrecht and Arnold's experiments revealed that triangular snowflakes begin with the same process of chemical bonding and forms a hexagonal shape.

　　F. NO CHANGE

　　G. were they to form

　　H. if they formed

　　J. form

　　【答案】J

　　【解析】In 2009, Libbrecht and Arnold's experiments(主句主语) revealed (主句谓语)/(宾语从句)that triangular snowflakes(从句主语) begin with(从句谓语1) the same process of chemical bonding(从句宾语1) and forms(从句谓语2) a hexagonal shape(从句宾语2).

　　Form 是snowflakes的谓语，与begin with并列，所以也应该用复数。

　　从上题可以看出，如果谓语并列，我们可以根据"平行原则"，通过其中一个谓语的形式来推定另一个谓语的形式。

　　3. 并列谓语：可以从其中一个谓语推出划线部分的单复数

　　例7：71C25

　　To hold the nearly weightless runner in place, a harness fastens around the runner's hips and shoulders and connect to the treadmill with bungee cords and clips.

　　A. NO CHANGE

　　B. are connected

　　C. connected

　　D. connects

　　【答案】D

　　【解析】这句话的主语为a harness，谓语为fastens and connect，但是fasten不划线，而connect划线，我们可知这里应该connect跟着fasten来。