noun
BAD : Tourism is the main resource of money for these people.
GOOD : Tourism is the main source of money for these people.
BAD : Teachers are often regarded as a resource of knowledge.
GOOD : Teachers are often regarded as a source of knowledge.
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resource = (1) something that can be used to make a particular task or activity easier: 'All the teaching resources - books, cassettes and so on - are kept in a special room.' (2) something that a country has and uses to create wealth, such as oil or natural gas: 'Brunei is rich in natural resources.'
source = the place where something comes from or the thing from which we can get it: 'We collect the information from various sources.' 'Beans and lentils are a very good source of protein.'