It is a new subject to explore and look for the methods and indexes to describe and depict the evolutional characteristics of seismic precursor complex picture.

探索、寻找描述、刻画地震前兆复杂图像演化特征的方法与指标，是地震预报研究的新课题。

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One key element in searching for life on Mars is the presence of methane in the Martian atmosphere As a simple carbon compound, methane is often a precursor to the formation of the complex organic chemicals that make life possible.

FORBES: Curiosity Sniffs The Martian Atmosphere But Finds No Sign Of Life