Oxford discover 6

But today they commonly use strong steel ________.

The ________ bridge, the arch bridge, and the suspension bridge.

In the past, engineers often used _______ to blast tunnels through rock.

Especially when they´re needed to cross a __________.

... but Earth´s ______ geography often makes that ______.

These bridges were often __________ by ropes,

When the Channel Tunnel was built, to ______ the United Kingdom and France...

And many other landforms that have to be __________.

Beam bridges are often used for short ______ of distance,

It depends on the ___________.

Engineers have been using bridges and tunnels to go over, under, or through these _________.