多项选择题The followings may be administration overheads: A、Depreciation of office buildings and equipment B、Office salaries C、Rent, rates, insurance, lighting D、cleaning, telephone charges
单项选择题一段长度为λ 2的无损传输线，特征阻抗为50Ω，若其一端开路，则从另一端看进去为（ ）特性。 A、开路 B、短路 C、电感 D、电容
