【明報專訊】"Look!" Oliver cried. "I've finally found a switch (開關掣) that I can reach to turn on the light!" Ordinarily that would be exciting news, but I don't think so in this case. "Why not?" Oliver asked. "Because you happen to be sealed inside the bulb (燈泡)," I told him. "I knew this was too good to be true!" Oliver sighed. When a light, an engine, a radio or something like that is turned on, the power or electricity (電力) that operates it is connected.