The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

They are working with heavy machinery.
Indeed, they’re building a TUNNEL.
Money Heist Season 1, Episode 11

Are the stewards responsible
for maintaining the TUNNEL?
Game of Thrones Season 4, Episode 7

So far they’ve confirmed
that they’re building a TUNNEL.
Money Heist Season 1, Episode 13

The Night's Watch
will let you through the TUNNEL
Game of Thrones Season 5, Episode 8

We need your TUNNEL.
Game of Thrones Season 4, Episode 10