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：(C) For example
舉例：承接前一句「動物能感受痛覺是為了自我保護」，這句舉一個具體例子說明（碰到燙的東西會痛，因此學會不再碰），For example 符合；In contrast（相反地）、Before long（不久後）、To begin with（首先，通常用於列舉開頭而非單一舉例）都不如 For example 自然。
四個選項都是句首常見的轉承語，背了中文意思就想直接套上去。這一題的鑑別度只有 32，但原因和難題正好相反：它本身不難，各種程度的人都答得出來，自然分不太出高下。要判斷的是最基本的一種篇章關係——前一句給原則，這一句給實例。
把前後兩句擺在一起看。前一句是通則：Animals are able to feel pain because they can use it for self-protection.（動物會痛，是因為痛可以拿來自保。）本句則是一個具體情境：if you touch something hot and feel pain, you will learn ... that you should not touch that item in the future（你碰到燙的東西會痛，於是學會以後別再碰）。一個抽象、一個具體，而且具體那句正好在示範前一句講的道理，這就是舉例，填 For example。
To begin with（首先）：用在列舉的第一項，後面要有第二項、第三項接上來才成立（95 年第 28 題就是靠 To begin with → ___ → Finally 這條列舉鏈定案的），而本篇後面既沒有 Second 也沒有 Finally。In contrast（相較之下）：需要前後兩件事並排比較，但這一句是延續前一句、不是掉頭；本篇真正要對比的地方在後面，用的是 On the other hand。Before long（不久之後）：講的是時間先後，本篇並不是按時間推進的故事。
for example／for instance（舉例來說）、take sth for example（以……為例）、such as（例如）、to begin with（首先、第一點）、before long（不久之後）、on the other hand（另一方面）。
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.