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.

LEONARD: What kind of emergency?
- Mathematical.
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LEONARD: What kind of emergency?
- Mathematical.
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LEONARD: What kind of EMERGENCY?
- Mathematical.
The Big Bang Theory Season 4, Episode 21

Emergency drill night
last night, huh?
The Big Bang Theory Season 5, Episode 15

What, and risk talking
to your mother? Have to
be some EMERGENCY.
Breaking Bad Season 2, Episode 9

That means you'll be
in the EMERGENCY room every weekend
Money Heist Season 1, Episode 6

Do we really have to sit for hours
in the EMERGENCY room?
The Big Bang Theory Season 10, Episode 6