If you're gonna spend that much money on a plane ticket, why not just go to Rome?

如果你非要花那么多钱买张机票，为什么不干脆去罗马？

youdao

Yes? Yeah, so I'm saying when you fix theta you get only a half plane, not a full plane I mean, it goes all the way up and down, but it doesn't go back to the other side of the z axis. Why?

请说，所以我说当固定θ时,得到的是半平面，而非全平面,它布满z-轴的一侧,但从不延伸到z-轴的另一侧，为什么？

youdao

You are not sleepy? Why don't we go for a walk up and down the aisle so that we can look around the plane?

你不困吗？妈妈带你在过道里来回走走好吗，在飞机上四处看看？

youdao