【单选题】听力原文: Today, most countries in the world have canals. Even in the 20th century, goods can be moved more cheaply by boat that any other means of transport. Some canals such as the Suez or the Panama, s...
【简答题】在如图所示的振荡电路中, C 1 = C 2 = 500pF , C = 50pF , L = 1mH ,问: (1) 该电路属于何种类型的振荡电路? (2) 计算振荡频率 f 0 ; (3) 若 C 1 = C 2 = 600pF ,此时振荡频率 f 0 又为多少?从两次计算的频率中能得出什么结论?
【简答题】The months and years went by. I had been Joe’s apprentice for four years. One evening, Joe and I were sitting in the village inn. A stranger came in, a big, tall man, with heavy eyebrows. The man had ...