...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.
答案：(B) exhausted
become exhausted（變得枯竭）表示化石燃料屬於不可再生資源，產量終將下降並枯竭殆盡；decayed（腐爛）、hollowed（挖空）、intensified（加劇）均不符合此處資源枯竭的語意。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
exhausted 這個字，你的印象大概只有「（人）筋疲力盡的」，很難立刻想到它講資源時是「被用光的」。decayed（腐爛的）反而看起來與化石燃料由有機物形成的印象搭得上，很容易被挑走。
空格前面的關係子句已經把答案定義完了：non-renewable resources, which will eventually decline in production and become ______（不可再生的資源，產量終將下降，並且變得 ______）。這裡的 and 連的是 decline in production 與 become ______ 兩個述部，兩邊方向必須一致——產量一路下滑，最後的結果就是用光。exhaust 當動詞是「用盡、耗盡」（exhaust the supply），被動的 be exhausted 就是「被用光」；人「筋疲力盡」其實是同一個意思用到身體上，把體力用光了，兩個意思接得起來。
decayed（腐爛、衰敗）講的是東西本身變質，但資源用完不是腐爛，而且真正腐爛的是幾億年前那些生物，不是現在的存量。hollowed（挖空的）用在物體被挖出空腔（a hollowed-out tree trunk），不用在存量上。intensified（增強的）方向相反，產量正在下降。
be exhausted（被用光、耗盡）、exhaust the supply（耗盡存量）、non-renewable resources（不可再生資源）、decline in production（產量下降）、eventually（最終、終究）、be dependent on（依賴）
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.