根据上下文和所给首字母，补全空格内的词，使对话通顺。
A: What are you doing?
B: I'm trying to f 1 my pen.
A: What's wrong with it?
B: I'm trying to get it to write more quickly.
A: Well, that's easy! Just writer faster!
B: I've tried that but it doesn't work. I think if I make a pen that has a machine in it. I'll be a 2 to write
faster.
A: That's a f 3 idea.
B: No, it's not. Thomas Edison said he liked people who had i 4 . I think this is a good idea.
A: But if the pen writes too fast, how will you be able to write neatly?
B: Good question. See, now you're thinking too. We can come up with the answer t 5 .
A: OK! You put the machine in the pen, and I'll try to use it to write quickly and neatly.
B: That's a good plan, isn't it? We just n 6 to keep working on it, and not give up.