单项选择题
A.绝缘层B.抗磁层C.老化层D.屏蔽层
A.≤0.1dBB.≤0.2dBC.≤0.3dBD.≤0.4dB
A.100B.500C.1000D.2000
A.T/CEC122.21B.T/CEC122.31C.T/CEC122.41D.T/CEC122.51
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