经常
I would like to fly in space.Absolutely.That would be cool.I used to just do personally risky things， but now I’ve got kids and responsibilities， so I can’t be my own test pilot.That wouldn’t be a good idea.But I definitely want to fly as soon as it’s a sensible thing to do.
I think that’s the single best piece of advice: constantly think about how you could be doing things better and questioning yourself.