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.

Leonel lingered
for SEVERAL hours.
Breaking Bad Season 4, Episode 8

Your Grace, in the past on SEVERAL occasions,
Game of Thrones Season 5, Episode 2

to help deal with SEVERAL troublesome
issues, such as the queen's imprisonment.
Game of Thrones Season 6, Episode 3

As you know, SEVERAL weeks ago
in our first encounter...
The Big Bang Theory Season 1, Episode 4

You have on SEVERAL occasions
made great claims
Game of Thrones Season 4, Episode 10