用来界定保护范围的阻抗我们称之为（  ）。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69478' and id < 4500807 and id<>'4500807' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69478' and id > 4500807 and id<>'4500807' order by id asc limit 5