Tim Bowen brings off a helpful summary of these useful phrasal verbs.
‘A team of inspectors has been brought in to investigate allegations of extremism in schools in England’s second city.’ Often used in the passive in this sense, bring in means to use the skills of a particular group or person. In the sense of attract or contribute, bring in can also be used to identify the reason that someone or something receives a particular amount of money, as in ‘Overseas students bring in more than £30 million a year in tuition fees alone’. Again, often used in the passive, bring in can also mean to introduce a new law, regulation, measure or system, as in ‘The government has indicated that new measures will be brought in to ensure that failings of this kind never occur again’.
Also with the sense of introduce, bring into can be used to mean to cause someone or something to be involved in something, as in ‘I don’t believe it is right to bring politics into sport’ or ‘Why are you bringing money into the conversation?’
If you bring something difficult off, you succeed it doing it against the odds, as in ‘Parker brought off one of the shocks of the tournament when he defeated the reigning champion in the opening round’.
To bring on means to be the cause of something bad, especially an illness, as in ‘She nearly died of hypothermia brought on by prolonged exposure to the freezing temperatures’ or ‘I’ve no idea what’s brought this on – he’s usually such a friendly dog’.