英語六級攻克閱讀關鍵句229. Prices fluctuate, in response to harvests

229. Prices fluctuate, in response to harvests, natural disasters and political instability; and when they rise, it takes some time before new sources of supply become available.

譯文　價格由于收成、自然災害和政局的動蕩而波動；當價格上升時，得過一段時間后才會出現新的供應源。

點睛　本句的主干是Prices fluctuate...；it takes some time...。其中，in response to引導原因狀語；before引導時間狀語從句。

fluctuate意為“波動，變動”。本句中的in response to為固定短語，意為“作為對……的回應”。如：

He only shrugged his shoulders in response to the question. 他只是聳了聳肩，作為對問題的回答。

instability意為“不穩(wěn)定；不安定”。如：

The riot can be considered a symptom of political instability. 這次暴動可以看做政治上不穩(wěn)定的征兆。