进行测试是一个复杂的问题，需要有长期的经验才能掌握。
Testing is a complicated problem and long experience is required for its mastery.
该参照件通常用于长期曝光测试。
This reference material is normally used for long-term exposures.
用压差法测试塑料薄膜的透气性，是一个长期使用的主流测试方法。
One of the main methods to test the gas permeability is using partial pressure difference.
用压差法测试塑料薄膜的透气性，是一个长期使用的主流测试方法。
One of the main methods to test the gas permeability is using partial pressure difference.
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