单项选择题
A.5% B.10% C.15% D.20%
A.10%~20% B.20%~30% C.25%~35% D.30%~40%
A.±1% B.±2% C.±3% D.±4%
A.不宜超过75% B.不宜超过50% C.不宜超过25% D.不受限制
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