A.60% B.70% C.80% D.90%
A.正負(fù)1% B.正負(fù)2% C.正負(fù)3% D.正負(fù)4%
A.大于等于3000MΩ B.大于等于5000MΩ C.大于等于10000MΩ D.大于等于20000MΩ