發現大家對於「by片語」這個考點的判斷莫衷一是。這裏，Dustin希望跟大家分享自己的理解。看到by介系詞片語時，除部分固定搭配外，普遍有以下四種情況：
1. 若by後面加動作（Ving）
則語意上表「藉由...（手段）」，修飾動作（該動作為目的）。
此時檢查重點：
修飾的動作跟by後面的動作，在語意上當「採行手段達成目的」的因果關係是否合理。
In contrast to large steel plants that take iron ore through all the steps needed to produce several different kinds of steel, small mills, by processing steel scrap into a specialized group of products（手段）, have been able to put capital into new technology and remain economically viable.（目的） （語意合理：藉由廢鐵再生來去得資本投入新科技研發）
＊注意：被修飾的動作可以是主動也可以是被動。
2. 若by後面加名詞（N）
則語意上表「被...」，也就是被動式裡發出動作的對象。
In contrast to large steel plants that take iron ore through all the steps needed to produce several different kinds of steel, small mills, by processing steel scrap into a specialized group of products（手段）, have been able to put capital into new technology and remain economically viable.（目的） （語意合理：藉由廢鐵再生來去得資本投入新科技研發）
＊注意：被修飾的動作可以是主動也可以是被動。
2. 若by後面加名詞（N）
則語意上表「被...」，也就是被動式裡發出動作的對象。
前方會修飾最接近的動詞/分詞/action noun。
此時檢查重點：
1) 前方若緊跟動作，則該動作一定要用被動語態。
2) 檢查該名詞是否在語義上可以做出該動作（也就是當成S+V來檢查）
Organized in 1966 by the Fish and Wildlife Service, the Breeding Bird Survey uses annual roadside counts along established routes to monitor changes in the populations of more than 250 bird species, including 180 songbirds.
1) 前方正確使用過去分詞organized表被動語態。
2) Fish and Wildlife Service推測應為一個部門，可以合理做organize這個動作。
3. 若by後面加量詞
則語意上表差距。
此時檢查重點：
通常前面會有表程度變化的動作，才會搭配上表差距的修飾語。
According to scientists at the University of Alaska, while the surface temperature of the globe has risen over the last century by about one degree Fahrenheit, the surface temperature in Alaska, Siberia, and northwestern Canada has increased（增加，動詞表程度變化） over the last thirty years by about five degrees.
此時檢查重點：
1) 前方若緊跟動作，則該動作一定要用被動語態。
2) 檢查該名詞是否在語義上可以做出該動作（也就是當成S+V來檢查）
Organized in 1966 by the Fish and Wildlife Service, the Breeding Bird Survey uses annual roadside counts along established routes to monitor changes in the populations of more than 250 bird species, including 180 songbirds.
1) 前方正確使用過去分詞organized表被動語態。
2) Fish and Wildlife Service推測應為一個部門，可以合理做organize這個動作。
3. 若by後面加量詞
則語意上表差距。
此時檢查重點：
通常前面會有表程度變化的動作，才會搭配上表差距的修飾語。
According to scientists at the University of Alaska, while the surface temperature of the globe has risen over the last century by about one degree Fahrenheit, the surface temperature in Alaska, Siberia, and northwestern Canada has increased（增加，動詞表程度變化） over the last thirty years by about five degrees.
4. 若by後面加時間
則語意上表「在...時間之前」。
此時檢查重點：
由於表一段時間，所以通常跟完成式（在...之前）
或者跟推測語氣（在未來的...時間之前）搭配。
Using a Doppler ultrasound device, a physician can detect fetal heartbeats by the twelfth week of pregnancy. （在懷孕十二週之前）
