试题详情

一工件长度尺寸的真值为L。7&P116=20mm,测量时,所允许的测量误差为ΔL=0.5mm,其测得值只能在()范围内。7&P116

A19.25~20mm

B19.75~20.25mm

C20~20.5mm

D19.5~20.5mm