题目

把一根电阻为1Ω的粗细均匀的金属丝截成等长的2段。再把这2段金属丝并联起来，这样并联后的总电阻是（ ） A . 0.05Ω B . 0.25Ω C . 4Ω D . 1Ω 答案：BIf you _____ to something different, for example to a different system, task, or subject of conversation, you change to it from what you were doing or saying before. [     ]A. switch B. appeal C. submit D. adapt