单项选择题
A.3d B.4d C.5d D.2d
A.400 mm B.600 mm C.800 mm D.500 mm
A.20℃±2℃ B.10℃~20℃ C.10℃~40℃ D.18℃~28℃
A.0.5% B.0.05% C.1.0% D.1%
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