756. To map Earth's interior, geologists use a network of seismometers to
chart seismic waves that originate in the earth's crust and ricochet around
its interior, most rapidly traveling through cold. dense regions and slower
through hotter rocks.

A. interior, most rapidly traveling through cold. dense regions and slower
B. interior, which travel most rapidly through cold, dense regions, and more
slowly
C. interior, traveling most rapidly through cold, dense regions and more
slowly
D. interior and most rapidly travel through cold, dense regions, and slower
E. interior and that travel most rapidly through cold, dense regions and
slower
Answer: C
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我們來看這題的句意表示，......seismic waves 到這裡句子已經完整結束
而後續表達的動作 originate (V1) and ricochet (V2), traveling (V3)
皆為 seismic waves 表達的動作

而 seismic waves 既然在後面加入了 that，
則新子句的主詞自然而然就成了 seismic waves

所以我們可以重新來這樣看子句:
seismic waves originate (V1) and ricochet (V2), traveling (V3)....
則這個 traveling 自然而然就是修飾 seismic waves，沒有問題

答案 (B) 的 which，在 GMAT 規則中就是修飾最近的名詞或整組名詞 (a of b)
所以無論如何都修飾不到 seismic waves

而同樣的用法也出現在 OG 2017 #767 當中

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767. The results of the company's cost-cutting measures are evident in its
profits, which increased five percent during the first three months of this
year after it fell over the last two years.

A. which increased five percent during the first three months of this year
after it fell
B. which had increased five percent during the first three months of this
year after it had fallen
C. which have increased five percent during the first three months of this
year after falling
D. with a five percent increase during the first three months of this year
after falling
E. with a five percent increase during the first three months of this year
after having fallen
Answer: C
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正確答案 C 的 after falling，falling 並不是修飾原句主詞 The results
而是修飾 profits

profits + which + increased.....
則後面產生的新子句為 profits increased.....after falling

主詞已經變成了 profits，所以 after falling 可以正確的修飾到 profits 沒有問題
(D), (E) 同樣使用 after falling，則因為前面子句唯一的主詞只有 the result，
無法修飾到 profits


※ 引述《Tsou2 (Ashton.Tsou)》之銘言：
: 最近在總結考點，突然想不透句尾Ving考點，所以上來請示各位大神們。
: 句尾Ving表達因果關係、表示伴隨發生的事情。
: 今天做到一題正要選Ving時卻卡住，因為我去檢查了邏輯主語，
: 發現主要子句的主詞不能做出Ving這個動作而是受詞要做，所以選到了錯誤答案。
: 貼一下今天做的題目：
: To map Earth’s interior, geologists use a network of seismometers to chart
: seismic waves that originate in the earth’s crust and ricochet around its
: interior, most rapidly traveling through cold, dense regions and slower
: through hotter rocks.
: A) interior, most rapidly traveling through cold, dense regions and slower
: B) interior, which travel most rapidly through cold, dense regions, and more slowly
: C) interior, traveling most rapidly through cold, dense regions and more slowly
: D) interior and most rapidly travel through cold, dense regions, and slower
: E) interior and that travel most rapidly through cold, dense regions and slower
: 分享我的做題思路，各路神人煩請不吝指教：
: 1) most rapidly和more slowerly平行，刪ADE
: 2) 原本要寫C，可是回頭去看traveling邏輯主語抓到geologists，心理一陣困惑。
: 做traveling這個動作的不是seismic waves嗎!!! 於是寫了B
: 3) B跳躍修飾指代seismic waves
: (後來查論壇that/which同時指代seismic waves是錯誤的)
: 謝謝大家，祝各位殺G順利。

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※ 編輯: ndxica (180.204.50.72), 06/15/2017 23:37:49

個人覺得 comma + Ving 也並不是 100% 指代原題主詞
但肯定和前面的事件 or 動作有相關性

1. 前面子句形容的事件:
Manhattan 有一個例句我覺得可以當參考:
Crime has recently decreased in our neighborhood, leading to a rise in
property values.

犯罪率下降，造成房地產上升。 -->
房地產上升的來源並不是犯罪，而是"犯罪率下降"整件事情

再拿一題經典題來測試:

In the mid-1970's, (since birds were overcome by pollution, and routinely
falling from the sky above Los Angeles freeways, this prompted officials in
California to devise a plan that reduced) automobile emissions.

D. birds overcome by pollution routinely fell from the sky above Los Angeles
freeways, prompting officials in California to devise a plan to reduce
E. birds overcome by pollution and routinely falling from the sky above Los
Angeles freeways were prompting officials in California to devise a plan to
reduce

基本句意為: 被汙染的鳥從LA高空墜弱，而促使官方立法降低汽車排放廢氣

促使官方立法，應該是前面整個事件 --> 被汙染的鳥從LA高空墜弱
而並非為鳥本生的意志 (答案 (E)) (鳥總不可能以死明志吧?)

所以答案必須選 (D)，使用 comma + Ving 的答案

2. 最接近動作的主詞

例子就是此題原題本身:

由於此題為 OG 題目，Manhattan 並沒有單獨此題的論壇，
但在這裡可找到 Ron 對此題的解釋
https://goo.gl/WO1TfP

'comma _ing' modifies the closest action.

here, that action is '...ricochet around [the earth's] interior.'
the subject of THAT action is 'seismic waves', and so 'comma + _ing' works
perfectly in the usual way.

最接近的動作為 originate and ricochet，主詞則為 seismic waves

※ 編輯: ndxica (180.204.50.72), 06/16/2017 03:01:58