Use of informal language:
- Nothing can't be done about it.
There is nothing that can be done about it.
- Global warming can't be real.
Global warming is unlikely.
- I think the government should prohibit smoking in public places.
The government, in my opinion, should outlaw/ban/prohibit smoking in public places. (-> this would be used in an essay/letter where you're allowed to voice your opinion. You can also leave out the linking words/phrase which turns the sentence subjective)
Please use the passive throughout your essay!