The geological hazard less exists alone. It often occurs in a group or family.

地质灾害很少单独发生，而常呈某种特定的群、族集体存在。

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The geological hazard less exists alone. It often occurs in a group or family.

地质灾害很少单独发生，而常呈某种特定的群、族集体存在。

youdao