It is a complicated problem.

这个问题错综复杂。

《新英汉大辞典》

It is a complicated problem involving several of subjects such as geology, coal mining, rock hydraulics and rock crack mechanics.

煤层底板突水是涉及地质学、煤矿开采学、岩体水力学和岩石断裂力学等学科的一个复杂问题。

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Resharding is a complicated problem, and it has the potential to cause major complications in the management of your production application if it is not considered during the design.

重新分片是个很复杂的问题，设计过程中如不加以考虑，可能会在管理生产应用程序时造成严重的并发状况。

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It is a complicated problem with which Obama will have to wrestle.

CNN: World to Obama: You can't ignore us

"It is without a doubt the most complicated problem I've ever had to solve, " says Kensey, who also invented a device to stop arterial bleeding during surgical procedures.

FORBES: The Plot Thickens

The development of the Tethyan Realm is such a complicated problem that it remains far from being clarified.

UNESCO: EARTH SCIENCES FOR SOCIETY