50 years ago,shenzhen was a small fishing village.It was very small.There weren't many people.There were not any tunnels.There were not any cars,busas,taxis,trains and plants,either.Now,there are very different from 50 years ago.Shenzhen became a big modern city.There are lots of people.There are a lot of tunnels.There are many cars,buses,taxis,trains and plants,too.