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.

Thank you, Raj, that was
a really nice INTRODUCTION.
The Big Bang Theory Season 12, Episode 5

Now, INTRODUCTION to physics.
The Big Bang Theory Season 3, Episode 10