Here are three short ways to say it:
- A subway zooms through tunnels under the streets.
- It skips street traffic, so it gets you around the busy city fast.
- An underground train runs in tunnels to take you quickly under the city.
Three short, simple lines a 7-year-old can use to say an underground train runs in tunnels and is a fast way to travel in a busy city.
Here are three short ways to say it: