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.

...an IMPROVEMENT
on the existing mediocre stock.
The Big Bang Theory Season 1, Episode 15

It's an IMPROVEMENT.
Game of Thrones Season 1, Episode 3

I imagine for most of them,
it would be an IMPROVEMENT.
Game of Thrones Season 7, Episode 7

Significant IMPROVEMENT
over the old neighbor.
The Big Bang Theory Season 1, Episode 1

Excuse me, l would be
a vast IMPROVEMENT.
Breaking Bad Season 4, Episode 8