However, it then became dangerously tempting to expand agriculture during wet decades with favorable growing conditions into marginal areas with less reliable springs and groundwater.

【翻译】然而，在有着良好生长条件的多雨的数十年里，把农业生产扩展到泉水和地下水没有保障的边缘地区，这在当时是非常危险的诱惑。

【理解和分析】主要句式：It became tempting to do sth. “做某事变得很有诱惑”。不定式是真正主语，it是形式主语。

本句的主要结构为：It became tempting to expand agriculture into marginal areas.

1. expand...into...把......扩展到

2. 在decades和 marginal areas之后，分别有一个with短语，作定语。

3. during wet decades作时间状语，修饰expand agriculture。