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.

because of some
SILLY Roommate Agreement.
The Big Bang Theory Season 5, Episode 15

Guess sometimes I'm SILLY.
The Big Bang Theory Season 9, Episode 9

- Well, now I just feel SILLY holding it.
- Come on.
The Big Bang Theory Season 4, Episode 19

Oh, you SILLY doodlebug.
The Big Bang Theory Season 6, Episode 8

I know it sounds SILLY.
The Big Bang Theory Season 3, Episode 17