Bridges are built over roads，rivers，or railways.They appeared a long time ago.Back then，they were built with stones，ropes，logs，and vines.Some were very simple，like a footbridge made out of a big tree.But today，bridges are bigger，stronger，and more modern.This is because we have better technology today.
Bridges are a mix of maths，physics，design，and architecture.They are designed by skilled engineers and they take years to build.
    Bridges must be so strong that they can support not only their own weight，but also the weight of the people and vehicles（交通工具）.People build it in a way that protects them from earthquakes，strong winds，and freezing.
    The three main types of bridges are arch，beam and suspension.Let's take a closer look at each one.
    Arch（拱）bridges were invented a long time ago by the Romans.They were built out of stone or brick，and stood on support structures in the shape of arches.Beam bridges are horizontal（水平的）beams supported by columns.These bridges are very old as well.Suspension bridges have a tower（索塔）on either side.The towers are connected by cables.They are more modern，with the first ones being used in the early 19th century.
    People all know that the oldest bridge in the world is the Zhaozhou Bridge in China.It's an arch bridge made out of stone that was built in 605 A.D.But if you're looking for the world's longest bridge，it would be the Danyang-kunshan Grand Bridge.It is also in China.It has a length of over 164.85 kilometres!

（1）Bridges have a long history.In the past，some were very

simple

simple

but now they are bigger，stronger，and more modern

because of with the help of

because of with the help of

today's better technology.
（2）The bridges must be

strong enough to

strong enough to

support the weight of the people，vehicles and themselves.They are built in a way that protects them from

natural disasters/dangers

natural disasters/dangers

like earthquakes，strong winds，and freezing.
（3）The passage tells us about

three

three

types of bridges including

arch，beam and suspension

arch，beam and suspension

.
（4）A long time ago，The Romans used stone or brick

to build

to build

arch bridges.The first suspension bridges

have been used/have been in use

have been used/have been in use

since the early 19th century.
（5）The Zhaozhou Bridge is

famous/known as

famous/known as

the world's oldest bridge while the Danyang-kunshan Grand Bridge is the longest one.They are

both

both

in China!