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.

Amy, MOURNING the inevitable
is a complete waste of time.
The Big Bang Theory Season 7, Episode 22

You sit alone in a darkened room
MOURNING their fates.
Game of Thrones Season 5, Episode 3

to facilitate MOURNING.
The Big Bang Theory Season 12, Episode 10

Mourning her dear departed boy.
Game of Thrones Season 4, Episode 4

You can sit here MOURNING its departure
or you can prepare for the future.
Game of Thrones Season 6, Episode 10