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.

Locked himself in his room
and built a sonic death RAY.
The Big Bang Theory Season 1, Episode 4

Wouldn't have been any ass-kickings
if that stupid death RAY had worked.
The Big Bang Theory Season 1, Episode 4

...teenagers running around
with RAY guns, right?
Breaking Bad Season 3, Episode 11

♪ A cathode RAY tube
without an electron gun ♪
The Big Bang Theory Season 7, Episode 6