Animals are able to feel pain 26 they can use it for self-protection. 27, if you touch something hot and feel pain, you will learn from this 28 that you should not touch that item in the future.
答案：(B) because
這句在解釋動物能感受痛覺的原因，because（因為）說明這是演化上的因果關係——動物能感受痛覺，是因為這個能力可以用來自我保護；雖然 so that（以便）從目的論角度也可以說得通，但接下來整段文章討論的是痛覺實際帶來的效果與運作方式（如「碰到燙的東西會痛，就學會不再碰」），比較貼近解釋「為什麼」的因果關係，這裡選because較為合理。
答對率 42％。先看四個選項的共同點：都是從屬連接詞，後面都能接完整子句，形態上一個也刷不掉，可見這一格考的不是形態，是兩個子句之間的邏輯關係，只能靠讀懂整段。最容易被拉走的是 so that——「動物能感受疼痛，好讓自己保護自己」聽起來很順。
回頭看這一篇是怎麼展開的。第二句已經先示範過一次同樣的句型：There is currently no reason to believe that plants experience pain, because they are devoid of central nervous systems and brains.（植物不會痛，因為牠們沒有中樞神經與大腦）——先講「會不會痛」，再用 because 交代生理上的原因。本句 Animals are able to feel pain ___ they can use it for self-protection. 是同一個框架的另一半：先講動物會痛，再交代原因。再往後看，plants cannot move from place to place and do not need to learn to avoid certain things, so this sensation would be unnecessary（植物不會四處移動，也不需要學著避開，所以這種感覺對牠們沒有必要）同樣是在講原因。整段從頭到尾都在回答「為什麼」，填 because 最一致。
so that（以便、為了）：引出的是目的，主詞通常是有意圖去做某件事的一方；而且整段要回答的是「為什麼動物會痛、植物不會」，不是「動物為了什麼而痛」。although（雖然）：方向相反，會變成「動物能感受疼痛，雖然疼痛可以拿來自保」，前後根本沒有轉折可言。when（當……時）：讀起來像「動物在能利用疼痛自保的時候才會痛」，把因果關係換成了時間關係，與整篇的說明脈絡對不上。
be able to V（能夠……）、be devoid of（毫無、缺乏）、use A for B（把 A 用於 B）、because of ＋ 名詞（因為……）、so that ＋ 子句（以便……）、experience pain（感受到疼痛）。
Do plants have feelings? There is currently no reason to believe that plants experience pain, because they are devoid of central nervous systems and brains. Animals are able to feel pain 26 they can use it for self-protection. 27, if you touch something hot and feel pain, you will learn from this 28 that you should not touch that item in the future. On the other hand, plants cannot move 29 and do not need to learn to avoid certain things, so this sensation would be unnecessary.
From a physiological standpoint, plants are completely different from animals. They cannot feel pain. Therefore, 30 animals' body parts, many fruits and vegetables can be harvested over and over again without dying.