Scientists expect it to increase an 21 2° to 6° F over the next one hundred years.
答案：(B) additional
additional 2° to 6° F（額外的2到6華氏度）表示在過去一世紀已上升近1°F 的基礎上，未來一百年還會再增加2到6度；extreme／immediate／original 均不符合此處語意。
四個選項都是形容詞，都能擺在 an 與數字之間，你會憑中文挑一個。
答對率不到五成。空格前是 increase an ______，後面接的是一個溫度的增幅（兩到六華氏度）。increase an additional ＋ 數量 是成組的說法，意思是「再增加多少」。為什麼是「再」：這一段的主題句 Average global temperature has increased by almost one degree Fahrenheit over the past century（過去一世紀全球平均溫度已上升將近一華氏度）已經先講過一次上升，空格這一句講的是未來一百年還要在那之上再加。填進去讀成 increase an additional two to six degrees（再增加兩到六度）。這一格真正該學起來的不只是這個字：同一個現象，文章前後會換不同的說法再講一次。主題句用 increased by（上升了多少），空格這一句改用 increase an additional（再增加多少），講的是同一件事的兩個階段。讀克漏字時把整段的核心概念放在心上，遇到空格先問一句「這是不是在把前面講過的事換個說法再說一遍」，很多格就是這樣定下來的。
extreme（極端的）是在評價幅度大不大，但這一句只是在報數字；immediate（立即的）講的是時間上的馬上，與「未來一百年」矛盾；original（原本的、最初的）指的是最早那一個，這裡講的卻是後來再增加的部分。三個都是形容詞，形態吻合，容易被順手選走。
an additional ＋ 數量（額外的、再增加的）、in addition（此外）、increase by ＋ 幅度（增加了多少）、average global temperature（全球平均溫度）、over the next hundred years（在接下來一百年）、original（原本的、最初的）。
Average global temperature has increased by almost 1°F over the past century. Scientists expect it to increase an 21 2° to 6°F over the next one hundred years. This may not sound like much, but it could change the Earth's climate as 22 before.
Climate change may affect people's health both directly and indirectly. For instance, heat stress and other heat-related health problems are caused directly by very warm temperatures. 23, human health can also be affected by ecological disturbances, changes in food and water supplies, as well as coastal flooding.
How people and nature 24 climate change will determine how seriously it affects human health. Generally, poor people and poor countries are 25 probable to have the money and resources they need to cope with health problems due to climate change.