一般情况下，不定冠词a/an一般是泛指人或者物，如果是第一次提到一个人或者一个物，要用不定冠词指代;定冠词一般是特指人或者物，如果是再次提到一个人或者一个物，要用定冠词。那么，有一种由不定冠词和定冠词先后出现的指代逻辑就产生了。
举例说明：从前有座山，山里有座庙。
Once upon a time, there was a mountain. (第一次提到这座山，用不定冠词指代)
Inside the mountain stood a temple.(第二次提到这座山，用定冠词指代)
掌握了冠词的指代逻辑，在做题目的时候就会轻松get到段落内部的结构和层次, 从而提高逻辑结构题目中的句子置位题的正确率。
Eg1.
[1]Thus, even though I already had all the equipment I needed in my home office, I decided to try using a coworking space in my city. [2]Because I was specifically interested in coworking’s reported benefits related to creativity, I chose a facility that offered a bright, open work area where I wouldn’t be isolated. [3]Throughout the morning, more people appeared. [4]Periods of quiet, during which everyone worked independently, were broken up occasionally with lively conversation.
The writer wants to add the following sentence to the paragraph. After filling out a simple registration form and taking a quick tour of the facility, I took a seat at a table and got right to work on my laptop.
The best placement for the sentence is immediately
A.Before sentence 1
B.After sentence 1
C.After sentence 2
D.After sentence 3
【答案解析】：所给的句子中有”a quick tour of the facility”, 可以断定，这个句子的前面的句子一定有“a facility”, 文中第二句中有“I chose a facility that...”, 所以果断选择C选项。
Eg2.
[1]Box’s research is important because the fires of 2012 may not be a one-time phenomenon. [2]According to scientists, rising Arctic temperatures are making northern latitudes greener and thus more fire prone. [3]The pattern Box observed in 2012 may repeat, with harmful effects on the Arctic ecosystem. [4]Box is currently organizing an expedition to gather this crucial information. [5]The next step for Box and his team is to travel to Greenland to perform direct sampling of the ice in order to determine just how much the soot is contributing to the melting of the ice sheet. [6]Members of the public will be able to track his team’s progress--and even help fund the expedition--through a website Box created.
To make this paragraph most logical, sentence 4 should be placed
A. where it is now
B. After sentence1
C. After sentence2
D. After sentence5
【答案解析】：第4句中有“an expedition”，那么如果再次提到expedition, 必然会用到“the expedition”, 通读全段之后发现，“to gather this crucial information”是指“perform direct sampling of the ice in order to determine just how much the soot is contributing to the melting of the ice sheet”, 所以可以断定sentence4应该放在第5句话之后，答案选D选项。
以上就是为大家整理的：SAT语法指代考点讲解，希望通过上述这些知识的学习，对大家接下里的SAT备考有更好地帮助。预祝同学们在接下里的考试中取得更好的成绩。