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.

- Dreadful.
- If you can't keep the king's peace,
Game of Thrones Season 1, Episode 4

How DREADFUL, isn’t it?
Money Heist Season 1, Episode 7

Ch'Vyalthan was a DREADFUL writer,
but an excellent researcher.
Game of Thrones Season 7, Episode 2

trying to take the focus
off that DREADFUL table
The Big Bang Theory Season 7, Episode 16