真的？这仪器用的什么原理？用反射波或超声波来测密度？

来源: 说的好于 2012-09-21 10:06:17 [旧帖] [给我悄悄话] 本文已被阅读：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.