【简答题】铬是常见的过渡金属之一,研究铬的性质具有重要意义。 (1) 在如图装置中,观察到装置甲铜电极上产生大量的无色气体;而装置乙中铜电极上无气体产生,铬电极上产生大量红棕色气体。由此可得到的结论是 ____________________________ ____________________________________________________________________ 。 (2) ...
【单选题】I woke up early,much earlier than I had expected.
【简答题】Today was a bit different—I was starting at college. I was very excited. I woke up early, much earlier than I had expected. I had thought I might sleep late as I did during the long vacation, but I wa...
【简答题】光电耦合器的主要工作原理是什么?其主要特点是什么?主要参数有哪些?
【简答题】I woke up early, much earlier than I had expected.