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.

...we need the appropriate words
to mark this HISTORIC scientific event.
The Big Bang Theory Season 2, Episode 12

Well, well, this is an HISTORIC day.
Game of Thrones Season 1, Episode 3

A trip to a HISTORIC railway
The Big Bang Theory Season 10, Episode 15