单项选择题
A.1.0m B.2.0m C.0.5m D.10m
A.0.1mm B.1mm C.0.2mm D.0.5mm
A.0.4d B.10cm C.5cm D.3cm
A.20~30S B.14~18S C.10~14S D.18~20S
微信扫一扫,加关注免费搜题