什麼是從屬連接（subordinating conjunctions）句型？
了解從屬連接句型能幫助您寫出複雜的句子，使段落句型更多元並同時避免寫出零散的片段短句。從屬連接句型能在概念間創造不對等的強調，一方面用獨立子句強調主要概念，另一方面將次要概念當作輔助陪襯。
一般來說，從屬子句通常以從屬連接詞或從屬字開頭。
什麼是獨立子句？
一個完整的句子基本組成會包含獨立子句和從屬子句。你可能會問：“他們有什麼不同呢？為何要分別？”兩者最大的差異就是獨立句子本身就可以表達完整的意思，而從屬子句則不一定。
首先，讓我們簡單說一下什麼是子句。子句是包含主詞和動詞的一組詞，它可能是句子的一部分或句子本身。
請看以下例句：
Michael laughed. => Michael笑了。（“Michael” 是主詞；“laughed” 是動詞；子句已經是一個完整的句子。）
Michael laughed because Sarah made a funny face. => Michael因為Sarah扮了個鬼臉而笑了。（子句“Michael laughed” 是句子的一部分。）
子句可以進一步分為獨立子句和從屬子句。下面我們將更詳細的帶您了解兩者的分別及用法，一起來看看吧！
獨立子句
獨立子句是包含主詞和動詞的短句，且已經表達了完整的思維，所以獨立子句可以獨立存在，不用再加上其他的東西。
Steven completed the proposal. => Steven完成了提案報告。
Dennis vacuumed the floor before eating. => Dennis吃飯前先吸了地。
從屬連接詞
- 對比：although, even though, while（雖然）
- 因果：because, since, as（因為）
- 時間：when（當……的時候）, whenever（無論何時）, while（當……時）, once（一旦）, before（在……之前）, after（在……之後）, since（自從）, until（直到）, as long as（長達）, as soon as（一……就）
- 條件：if（若）, when（當……的時候）, provided that（假若）, in case（假使）, assuming that（假定）, as long as（只要）
- 地方：where（在……哪裡）, wherever（無論何處）
- 否定條件：unless（除非）
- 選擇條件：whether or not（是……或不是）
從字義上大概可看出，從屬連接句型是用來創造次於主要獨立子句的從屬子句；在這類句型中，獨立子句強調主要概念，次要概念則當輔助陪襯。至於選擇強調哪一個子句則由作者決定，無論句中哪一個概念轉為從屬子句均會改變句子的重點。
請看以下例句：
As I continued to explain my reasoning, my subconscious thoughts became clearer.
Although my subconscious thoughts became clearer, I continued to explain my reasoning.
在第一句裡，「我的潛意識」是重點，第二句強調的則是「我繼續解釋他的思考邏輯」。從屬子句和主要子句以逗號作區隔，單一從屬字句僅是句子片段，並非完整句。例如：“Although my subconscious thoughts became clearer” 便不是一個完整的句子。合併獨立子句和從屬子句的範例（下方有下引線的為獨立子句）：
Even though I am not exactly a fan of Lady Gaga, I could not pass on a free concert ticket.
Since becoming a father, I have not slept for more than six hours a day.
透過概念的從屬化使句子有重心
假設一個句子內包含兩個不同概念，在比較過後可將不重要的概念轉為從屬子句。
一個具備主要和次要概念的句子可作為良好的論文陳述基礎，因為這樣的句子能暗示論文的重點並透露觀點背後的推論過程。將某些概念轉為從屬子句也有助於加強句子和段落間轉折的流暢性。
假設您要合併這兩個概念：
Fewer and fewer fish are left in the ocean.
An increasing number of fishermen fish during the bleak winter months.
您可將句子合併來強調“漁夫越來越多”（主要概念）：
An increasing number of fishermen fish during the bleak winter months, so fewer and fewer fish are left in the ocean.
您也可以在合併句子時，將“魚越來越少”的事實作為主要概念：
Fewer and fewer fish are left in the ocean because an increasing number of fishermen fish during the bleak winter months.
在這兩個例子中，主要概念都可獨立作為一個完整句，而從屬概念以從屬連接詞“so” 和“because” 開頭，暗示了句子接下來的資訊較不重要。
控制句子重點
我們常在不經意間使用了從屬和對等連接句型；舉例來說，如果要描述某事發生是因為另一件事所造成，例如：“David broke his leg while riding a scooter” 或 “David broke his leg when he crashed his scooter into a telephone pole”，可以用幾個不同句子或一個從屬連接句型表達。
以兩個句子呈現：David broke his leg while riding his scooter this weekend. His leg broke when the scooter hit a telephone pole.
用一個從屬連接句呈現：This weekend, David broke his leg when his scooter hit a telephone pole.（“David跌斷腿”是主旨，“這件事在摩托車撞到電線桿時發生的”則是從屬的句意。）
當在討論假期要做的兩件事時，常會很自然地使用對等連接。這兩件事能以分開的句子呈現或以一個對等連接句型表示兩件事同等重要。
以兩個句子呈現：I am planning to go to Tokyo when I visit Japan. I am also going to go to Fuji Mountain.
以一個對等連接句型呈現：When I visit Japan, I am planning to go to Tokyo and Fuji Mountain.
從屬連接錯誤
請避免以下兩種常見的從屬連接錯誤：一、將主旨放在從屬子句中，二、一個句子放太多從屬子句。
將主旨放在從屬子句中的錯誤示範：
Torishiki, a classic Yakitori restaurant featuring great food and dining experience, is located in Tokyo.
這一句的問題在於將主旨嵌在從屬子句中，不但沒有凸顯出餐廳的特色，反而使餐廳位於東京這件事成為句子重點。以下是修改的範例：
Torishiki, located in Tokyo, is a classic Yakitori restaurant featuring great food and dining experience.
若一個句子有太多附屬子句會變得難以理解且不易閱讀。
錯誤示範：
University professors, who make decisions about which textbook chapters to ignore and which to extend, need to consider more than their individual opinions so that they do not throw out great textbooks they do not recognize as good when they see them, while balancing the need to maintain a course that appeals to a broad class, considering that new textbooks do not yet have a broad following.
修改範例：
University professors need to consider more than their individual opinions when they decide which textbook chapters to ignore and which to extend. Many years ago, some of these very professors decided that currently popular textbooks should be thrown out, clearly demonstrating that they do not always know which books would become great. University professors should also balance the need to maintain a course that appeals to a broad class with an appreciation for new textbooks that do not yet have a broad following.
