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.

...though it may be hopeless
and FUTILE.
Breaking Bad Season 3, Episode 12

in a FUTILE attempt
to pick up some lonely postdoc,
The Big Bang Theory Season 7, Episode 1

I would advise the three of you
that resistance is FUTILE.
The Big Bang Theory Season 3, Episode 17