Building on civilizations that preceded them in coastal Peru, the Mochica developed their own elaborate society, based on cultivating such crops like corn and beans, the harvesting of fish and shellfish, and exploiting other wild and domestic resources.
Building on civilizations that precede them in coastal Peru, the Mochica developed their own elaborate society, "based on the cultivation of crops as corn and beans, the harvesting of fish and seafood, and the exploitation of" other wild and domestic resources.
以上是正解的句子,这个题目的关键点是对称和固定搭配,这些我都能理解。可是今天看这个句子的时候,突然发现一个小细节,就是在based on前面的那个逗号,我不明白为什么那里会有一个逗号,我觉得一个句子的结果应该是这样的:sb developed sth based on ```.如果based on前面加了一个逗号,那based on 在整个句子里会不会修饰不清,而且它在句子里的结构成分属于什么呢?