「Question No. 51」
Humans arrived in the Kaliko Islands about 7,000 years ago, and within 3,000 years most of the large mammal species that had lived in the forests of the Kaliko Islands had become extinct. Yet humans cannot have been a factor in the species' extinctions, because there is no evidence that the humans had any significant contact with the mammals. Further, archaeologists have discovered numerous sites where the bones of fish had been discarded, but they found no such areas containing the bones of large mammals, so the humans cannot have hunted the mammals. Therefore, some climate change or other environmental factor must have caused the species' extinctions.
Write a response in which you examine the stated and/or unstated assumptions of the argument. Be sure to explain how the argument depends on these assumptions and what the implications are for the argument if the assumptions prove unwarranted.
First of all, since humans may have done activities that deprived the mammals of their food or reduce the food supply or that destroyed the mammals’ habitats, ← 句型技法：用原因狀語從句引出對于“它因”的陳述。humans’ significant contact with the mammals may not be the cause of the mammals’ extinction as the author suggests. For example, humans may have cut down trees, which may have been the mammals’ source of food, ← 用定語從句建立人類活動對于哺乳動物食物源的影響。and meanwhile built housing on the grasslands, which may have been the mammals’ habitats ← 用定語從句建立人類活動對于哺乳動物棲息地的影響。. As a result, the mammals had become extinct because of the loss of food supply and habitats.
邏輯點思路2（常見邏輯疑點：偷換概念：打獵等同于產生丟棄的骨頭 / 它因問題：沒有丟棄的骨頭的原因不一定是沒有狩獵。）：
The author also assumes that hunting would have surely produced discarded bones and that, otherwise, no hunting would have taken place. ← 寫作步驟：上來就直接說明作者的assumption是什么。However, it is likely that the reason of that no large mammals’ bones had been found is mammals’ bones had been made to be tools and ornaments.← 寫作步驟：然后分析作者assumption的錯誤。如果理解為它因問題，那么就在此舉出典型的/在常識上最有可能的其它原因。For example, the large ones may have been made weapons and the small ones may have been made jewelries.← 寫作步驟：就著上一步的分析進一步展開，比如舉例進一步詮釋。Therefore, although there are no discarded mammals’ bones, humans may still have hunted the mammals. ← 寫作步驟：得出關于這一個邏輯疑點的小總結。