SAT文法知识系列栏目说明：每期分享3-5个文法知识点，帮助大家更好地备考SAT。

一、平行结构

1. 含义：

两个或两个以上句法、功能相同的词，词组或句子，通过并列连词、并列词组连接起来而构成，共同承担句子的某一成分的结构叫做平行结构。

2.类型：

（1）两者平行：要求前后平行的固定搭配

1) not only A but also B

2) both A and B

3) either A or B

4) neither A nor B

5) not A but/rather B

6) A rather than/instead of B

7) prefer A to B

8) prefer doing A to doing B

9) prefer to do A rather than do B

10) would rather do A than do B

（2）三者平行

a, b, and/or c

3. 用法

（1）固定搭配前后的形式和功能完全一致

例如1：两者平行

The computer company has increased sales for three consecutive years, both by lowering prices on its personal computers and by adding new product lines. 

解析：固定搭配为both a and b，both后面的形式是by doing的形式，所以and后的与其一致，所以是by adding。

（2）三者前后的形式和功能完全一致

例如2: 三者平行

The night before the playoffs began, the coach advised her players to eat a balanced dinner, to relax and enjoy themselves, and to get plenty of rest. 

解析：句中的to eat, to relax与to get三者平行。

题目检测

题目检测 1

Smith gave his plans for his country, plans that included, among other characteristics, supermarkets, factories, schools, and parks.

A. NO CHANGE

B. characteristics; supermarkets, factories, schools, 

C. characteristics; supermarkets, factories, schools

D. characteristics: supermarkets, factories, schools,

解析：通过题中的and看出是平行结构的考点，根据“三者前后的形式和功能完全一致”的原则，且B和C项的分号前后要一致，显然两项前后不一致排除B/C；而among other characteristics是插入语，不能用冒号，排除D，所以选A。

题目检测 2

The government regards this land as a heritage, national preservation, or other types of limited area can restrict activities such as logging and digging sands for building materials.

A. NO CHANGE

B. type of limited area

C. type of limited areas

D. limited area types

解析：通过题中的or看出是平行结构的考点，or前面a heritage是单数形式，根据“固定搭配前后的形式和功能完全一致”所以or后面需要用单数，所以排除A/C/D选项，所以选B。

题目检测 3

If people cut the watermelon in half, they will found its seed on the sharp knife or in the juicy melon.

A. NO CHANGE

B. in the melon’s juice

C. in the juice 

D. the juice of the melon

解析：通过题中or看出是平行结构的考点，or前面是on the sharp knife，on+形容词+名词的形式，根据“固定搭配前后的形式和功能完全一致”所以or后面需要用这种形式，所以排除B/C/D选项，所以选A。

题目检测 4

The British health-care system has made some progress on medical charts, which include information such as medicines, chronic diseases, and appointments with doctors. 

A. NO CHANGE

B. diseases; and

C. diseases: and

D. diseases and, 

解析：通过题中的and看出是平行结构的考点，根据“三者前后的形式和功能完全一致”的原则，medicines与chronic diseases用逗号隔开，所以本题因该用逗号，排除B/C；而D项and后不能加逗号，所以排除D，所以选A。

题目检测 5

They don’t need fish and chips, they don’t need to watch TV series and being less likely to be disturbed by loud noises. All they need to do is to concentration on studying for this final exam.

A. NO CHANGE

B. because they are

C. they are

D. DELETE the underline portion.

解析：通过题中的and看出是平行结构的考点，根据“三者前后的形式和功能完全一致”的原则，题中是前两个是独立的句子，所以第三个部分应该也是独立的句子，而A项单词、B项只是从句和D项删除，三项均存在句子结构不完整的情况，所以排除A/C/D,所以选B。