A.電阻 B.電流 C.電壓 D.頻率
A.1~2天 B.2~3天 C.3~4天 D.5天
A.應(yīng)力計(jì) B.復(fù)位計(jì) C.應(yīng)變計(jì) D.無(wú)應(yīng)力計(jì)