Agricultural complex system has the special functions and how to comprehensively analyse and evaluate it is till the problem of ecosystem research.

农业复合生态系统是具有特定功能的复合体，如何全面地分析和评价农业复合生态系统，目前仍是困扰生态系统研究的难题。

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Others emphasize the influence of complex and hierarchical human societies, and agricultural surpluses to be raided.

另一些专家则强调人类社会的复杂性和等级制度造成的影响，以及农产品出现剩余，引发掠抢。

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Combine harvester is a complex agricultural machinery with high-tech, its maintenance and custody is particularly important.

联合收割机是结构复杂、科技含量较高的农业机械，其维护保养与保管尤为重要。

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HILLAH, Iraq (CNN) -- American troops met stiff resistance Tuesday morning from Iraqi paramilitary forces for control of an agricultural complex on the outskirts of the central town of Hillah.

CNN: Fedayeen fights hard in Hillah

Africa's agricultural problems are complex.

BBC: Could GM crops help feed Africa?

At present, the rules for wine are among the most complex for all agricultural products.

ECONOMIST: Charlemagne