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.

I've got a SUBJECT wired up
for a sensory study.
The Big Bang Theory Season 12, Episode 5

Is it me or are you purposely
changing the SUBJECT?
The Big Bang Theory Season 10, Episode 7

I've been accepted as a test SUBJECT
for a drug...
The Big Bang Theory Season 1, Episode 15

the same or different as when
we speak about the SUBJECT of a king?
The Big Bang Theory Season 10, Episode 7

And on the SUBJECT of SUBJECTs,
is your use of the word "SUBJECT"
The Big Bang Theory Season 10, Episode 7