摘要：精选TED. 每个音频不超过2分钟，学英语和吸收伟大思想两不误
音频： https://n1audio.hjfile.cn/st/de745862-d5f4-4ef4-9218-d79361ca8512.mp3
原文：
01:17
EM: Yeah, absolutely. So this is the first time -- Just to show what we're talking about. So a couple of key things that are important in having a 3D tunnel network. First of all, you have to be able to integrate the entrance and exit of the tunnel seamlessly into the fabric of the city. So by having an elevator, sort of a car skate, that's on an elevator, you can integrate the entrance and exits to the tunnel network just by using two parking spaces. And then the car gets on a skate. There's no speed limit here, so we're designing this to be able to operate at 200 kilometers an hour.
01:59
CA: How much?
02:00
EM: 200 kilometers an hour, or about 130 miles per hour. So you should be able to get from, say, Westwood to LAX in six minutes -- five, six minutes.
02:13
(Applause)
02:17
CA: So possibly, initially done, it's like on a sort of toll road-type basis.
02:21
EM: Yeah.
02:22
CA: Which, I guess, alleviates some traffic from the surface streets as well.
02:26
EM: So, I don't know if people noticed it in the video, but there's no real limit to how many levels of tunnel you can have. You can go much further deep than you can go up. The deepest mines are much deeper than the tallest buildings are tall, so you can alleviate any arbitrary level of urban congestion with a 3D tunnel network. This is a very important point. So a key rebuttal to the tunnels is that if you add one layer of tunnels, that will simply alleviate congestion, it will get used up, and then you'll be back where you started, back with congestion. But you can go to any arbitrary number of tunnels, any number of levels.
03:05
CA: But people -- seen traditionally, it's incredibly expensive to dig, and that would block this idea.