Those who take pride in being decisive often try their best to consider all the factors beforehand. 29 , it is not unusual for them to come up with a decision before they have the time to do so.
答案：(A) However
語意轉折：「他們努力想要事先考慮所有因素，然而，他們卻常常在還沒時間充分考慮前就做出決定了」，這是一種「努力想周全卻仍然倉促決定」的反差對比，However（然而）符合這種轉折語氣；Furthermore（此外）、Conditionally（有條件地）、Similarly（同樣地）都不合。
However 這個字你國中就會了，看到題目大概覺得穩了。但這一題的鑑別度只有 15，低得反常——答對的人裡面，程度好的與程度普通的比例幾乎一樣，高分群考生並沒有在這一格拉開差距。原因不在 however 本身，而在後半句你有沒有真的讀懂。
關鍵在 before they have the time to do so 的 do so。do so 是替代用法，用來代替前面出現過的整個動詞片語，避免重複。這件事你國中就學過：Do you like it?—Yes, I do.（do 替代 like it）、When in Rome, do as the Romans do.（後面的 do 替代前面的動作）。本題的 do so 替代的是前一句的 consider all the factors beforehand（事先考慮所有因素）。把它還原出來再讀一次：前一句 Those who take pride in being decisive often try their best to consider all the factors beforehand.（以果斷自豪的人往往盡力事先考慮所有因素）；本句還原後是 it is not unusual for them to come up with a decision before they have the time to consider all the factors beforehand.（他們常常還來不及考慮所有因素，就已經做出決定了）。還原之後，兩句的反差立刻浮出來：想要考慮周全，卻根本來不及考慮就決定。這是清清楚楚的轉折，只有 However 接得上。沒有把 do so 還原的人，讀到 before they have the time to do so 只有一個模糊的「在他們有時間之前」，抓不到反差；這時 Furthermore 看起來也能接受。這正是鑑別度被拉低的原因：讀懂與沒讀懂的人在這一格看到的句子不一樣，而沒讀懂的人並不會發覺自己沒讀懂，於是憑語感選，選對選錯都成了隨機。再補一層確認：主旨句就在第一行 Most human beings actually decide before they think.（大多數人其實是先做決定才思考）。本句是這個主旨的再一次印證，而印證的方式正是「本來想周全、結果沒做到」的反差。
Furthermore（此外）：用來追加同一個方向的新論點，本句與前句方向相反，不是追加。Conditionally（有條件地）：副詞，意思是「附帶條件地」，沒有銜接兩句邏輯的功能，語意也對不上。Similarly（同樣地）：用來標示兩件事情況相似，本題前後句正好相反。
take pride in（以…為傲）、try one's best to do（盡力做…）、come up with（想出、提出）、do so（這麼做，替代前面提過的動作）、It is not unusual for somebody to do（某人常常…並不稀奇）、beforehand（事先、預先）。
Most human beings actually decide before they think. When people encounter a complex issue and form an opinion, how thoroughly have they 26 all the important factors involved before they make their decisions? The answer is: not very thoroughly, 27 they are executives, specialized experts, or ordinary people in the street. Very few people, no matter how intelligent or experienced, can 28 all the possibilities or outcomes of a policy or a course of action within just a short period of time.
Those who take pride in being decisive often try their best to consider all the factors beforehand. 29 , it is not unusual for them to come up with a decision before they have the time to do so. And 30 an opinion is formed, most of their thinking then is simply trying to find support for it.