新航道上海學校SAT培訓班小編繼續給大家帶來SAT文法第十四期，每期分享3-5個文法知識點，幫助大家更好地備考SAT。

  一、連接詞

  1. 含義：

  主要考察連詞的句內關系和副詞的句間關系。

  2. 類型：

  (1) 從屬連詞的句內關系

  ① 連詞although、though 引導讓步狀語從句連詞if、unless引導條件狀語從句;

  ② 連詞because、as、since引導原因狀語從句;

  ③ 連詞when、while、before、after、until、since、as soon as等引導時間狀語從句。

  3. 用法

  (1) 從屬連詞

  由于從屬連詞將從句與主句連接起來，從句不可獨立，是依附于主句，因此:

  1)從屬連詞引導的從句在主句前時，從句后要用逗號;

  2)從句在主句后時，通常無逗號;

  3)從屬連詞前后都無逗號;

  4)兩句僅需要一個連詞。

  例如 1：Because Tom likes drinking coffee, he normally buys one from the cafe.

  (because引導的從句在主句前，要用逗號隔開。)

  例如 2：Tom was late for work because he missed the train.

  (because引導的從句“because we missed the bus”在主句后面，此時不用逗號。)

  以上兩個句中because前后都無逗號。

  例如 3：Because Tom likes drinking coffee, and he normally buys one from the cafe. ?(because連接兩句，無需再加連詞and。)

  所以，連詞前面后面要不要加逗號，要依據情況而定。

  真題檢測

  真題檢測1

  (16-11AS Q26) While rare works were tucked away in libraries around the world and many are now also a click away on the Internet.

  A. NO CHANGE

  B. world;

  C. world,

  D. world however,

  解析：通過句首的while看出是連詞的考點，根據“從屬連詞引導的從句在主句前時，從句后要用逗號”的原則排除選項C;又根據“兩句僅需要一個連詞”的原則排除所以排除選項A和D，所以選B。

  注：16-11AS Q26指2016年11月亞太的第25題，下同。

  真題檢測2

  (17-08NA Q21) Although Duchenne made his observation about the orbicularis oculi enjoyment smiles as far back as 1862, it has been only in the recent past that empirical evidence has confirmed the existence of there being a high correlation between the contraction of the muscle and self-reported positive moods along with neural activity consistence with positive emotional states.

  A. NO CHANGE

  B. but it has

  C. while it has

  D. it having

  解析：通過句首although等看出是連接詞的考點，根據“兩句僅需要一個連詞”，排除B/C選項;而D選項有無謂語動詞，句子結構不完整，也排除，所以選A。

  真題檢測3

  (17-10NA Q12) While fare-free policies do increase ridership, but they have not been found to be an effective way to address traffic problems.

  A. NO CHANGE

  B. ridership, and while

  C. ridership,

  D. ridership;

  解析：通過句首while等看出是連接詞的考點，根據“兩句僅需要一個連詞”，排除A./B選項;又根據“從屬連詞引導的從句在主句前時，從句后要用逗號”排除D，所以選C。

  真題檢測4

  (17-10NA Q12) Advocates of fare-free policies claim that the costs of these policies are largely offset by various savings, however, a recent study comparing projected results of fare-free policies in different cities found this outlook to be way too sunny.

  A. NO CHANGE

  B. savings,

  C. savings, but

  D. savings; and

  解析：通過選項but等看出是連接詞的考點，however是副詞，不能單獨分隔兩個獨立句，所以排除選項A;而逗號不能單獨分隔兩個獨立句，所以排除選項B;分號和and都可以分隔兩個獨立句，因此重復，所以排除D;又根據“兩句僅需要一個連詞”，所以選C。

  真題檢測5

  (17-10NA Q12) Dried collodion is unusable, so once the photo is snapped with a massive, tripod-mounted camera, the photographer has nominal minutes to develop it, using more chemicals.

  A. NO CHANGE

  B. but

  C. and

  D. for

  解析：通過選項so等看出是連接詞的考點，前半句說火棉膠一旦干了就無法用了，后半句說攝影師有幾分鐘去發展它，所以前后是因果關系，排除選項B/C/D，所以選A。

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