【填空题】Early Computers Intern: I’m studying early...

【填空题】Early Computers Intern: I’m studying early computers in my Intro to Computing course. Technology is so much more advanced now! Engineer: Yes, we’ve come a long way since the days of vacuum tubes. Intern: Definitely. We watched a （1） program about those. It said that tubes failed practically every day. Can you imagine that？ Engineer: I’m sure it was really frustrating. Intern: Solid-state （2） is so much better. Hard drives hold so much more information. And they’re way more reliable. Engineer: Well actually, a hard drive isn’t solid-state. It’s electromechanical. Intern: Really？ I thought they were made from solid parts. Engineer: Technically, that's true. But （3） with moving parts aren’t really solid-state. Intern: Oh, okay. I thought solid-state just meant it didn’t have （4） tubes. Engineer: No, solid-state electronics are made out of semiconductors. Intern: That means they have both electrons and （5） holes, right？