单项选择题
A.8Ω B.9Ω C.10Ω D.12Ω
A.4s B.5s C.6s D.7s
A.1s～2s B.2s～3s C.2s～4s D.3s～5s
A.5V B.6V C.8V D.10V
微信扫一扫,加关注免费搜题
