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.

as soon as she gets tired
of the CLEVER words
Game of Thrones Season 7, Episode 7

My father will ask you if there's anything
more, and you'll tell him some CLEVER lie.
Game of Thrones Season 4, Episode 2

If he was so CLEVER,
Game of Thrones Season 7, Episode 3

He may look very CLEVER, but...
Money Heist Season 1, Episode 11

Oh, that's CLEVER.
The Big Bang Theory Season 7, Episode 3