One 11 of using fossil fuels is that it can generate large amounts of energy by the simple process of burning.
答案：(D) advantage
advantage（優點）表示使用化石燃料的一項優點是能透過簡單的燃燒過程產生大量能源；grace（恩典）、source（來源）、problem（問題）均不符合此處正面語意（後文才轉折談到缺點）。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
整篇一直在講化石燃料帶來的麻煩（vulnerable、pollution、risks），先入為主之下很容易覺得這一格要填 problem；source 也很誘人，因為「化石燃料是能源的來源」讀起來很順。
這一句的結構是 One ______ of using fossil fuels is that ...，be 動詞後面那個 that 子句就是空格的定義，把它讀完等於答案已經寫在紙上：it can generate large amounts of energy by the simple process of burning（燒一燒就能產生大量能源）。那是好處，所以填 advantage。這種「主詞裡有個空格、後面用 is that 把它解釋清楚」的句子，一律先跳到 that 子句去讀，比在四個選項之間猜快得多。全篇的走向也支持它：第 11、12 兩格先講兩個優點，第三句才用 However 轉到缺點，前一句的 vulnerable 不能拿來決定這一格。
problem 方向相反，填進去會變成「問題是它能產生大量能源」，語意矛盾。source 的常見組合是 a source of energy（能源的來源），但這裡是 One ______ of using fossil fuels，of 後面接的是「使用」這個行為而不是能源本身，而且 source 也接不住 is that 這個定義句。grace（優雅、恩典）與這個語境無關。
an advantage of ＋ V-ing（做某事的優點）、The advantage is that ...（優點在於……）、a source of energy（能源的來源）、generate energy（產生能源）、fossil fuels（化石燃料）、by the simple process of ＋ V-ing（藉由……這個簡單的過程）
Modern societies have become increasingly vulnerable in their dependence on fossil fuels such as coal and petroleum. One 11 of using fossil fuels is that it can generate large amounts of energy by the simple process of burning. 12 , fossil fuels are readily available and are currently plentiful.
However, the burning of fossil fuels leads to the release of pollution into the atmosphere. Dependence on fossil fuels from unstable regions or countries creates energy security risks for dependent countries. Oil dependence 13 has led to monopolization, war, and socio-political instability.
Most importantly, fossil fuels are considered non-renewable resources, which will eventually decline in production and become 14 , with serious consequences to societies that remain highly dependent on them. Fossil fuels are actually slowly forming continuously, but we are using them up 15 approximately 100,000 times faster than they are formed.