求翻译：a）三个试样都作废；是什么意思？

a) Three specimens are void;

A) 3 samples are obsolete.

To each batch of thin size material when carries on the conductivity experiment with the method of superposition, selects a b c three test specimens, presses down the table position to perform three time overlap conductivity experiments, discovered when second experiment, the conductivity surpasses

A) three samples are void;

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